Without Litecoin, Bitcoin would be 51% attacked.
The current amount to 51% Bitcoin according to https://www.crypto51.app/ for 1 hour, is $1,366,351. A good chunk of change. And that's just one hour. According to this website the U.S. Government spends 6.85 million dollars per minute, yes per minute. You'll quickly realize that it wouldn't be that hard to divert some government resources and engage in a full-scale attack on Bitcoin. How many hours would one need to reorganize the blockchain and cause distress? IDK. To learn more about 51% attacks you can read this.
Just know that it is theoretically possible to attack Bitcoin. The final dollar (or any other fiat money) amount to once and for all destroy Bitcoin is much much higher than the above amount. Understand that it is possible to at least initiate an attack on Bitcoin, but seemingly not probable. The possibility stems from the fact that since governments own the printing press, they can just print the money that is needed to engage in the attack itself. The government would surely have some explaining to do if they were to engage in a Bitcoin attack. If they ever did engage in an attack, it would probably be a covert operation. If they did the attack overtly, they would have to come up with some shady reasoning.
They could use the following "white knight" reasons: "Bitcoin threatens our national security". And they can blame things like money laundering, terrorism, financial terrorism, etc. Make no mistake about it, Bitcoin is a threat to the U.S. Dollar and other fiat currencies. So it's not inconceivable that governments may find a need to dismantle Bitcoin. It threatens at least part of why the State is so big. Issuing money is a massive source of power to our governing bodies. Not all of it was done with ill intent: because of gold's shortcomings there was a need for government to create fiat currencies. I understand this point will be hotly debated, but for the purpose of this article, whatever :)
Gold was used for much of history up until about the early 20th century. Gold was the primary money. For a number of reasons (some nefarious, some legitimate), gold was dropped, and Fiat currencies took center stage. U.S. Dollars, Chinese Yuan, Japanese Yen, South Korean Won, the Euro, British Pound, Indian Rupee, etc. are the dominant fiat currencies of the world. These fiat currencies are basically how the world goes round. Governments get to issue the money, control the money, and use the money at their own whims. The people are dependent upon them. Bitcoin has the power and possibility of taking that specific power away, totally creating a different landscape for government's purpose, and thus a massive threat to at least part of their existence. So governments probably do have a natural desire to at least entertain the thought of attacking Bitcoin. Bitcoin disrupts part of their legitimacy. Regulations can be put in place, as well as propaganda against Bitcoin. But I think those will ultimately fail because Bitcoin has won the heart and minds of people across the globe. Plus the facts are on the side of Bitcoin being a massive net good. There are warriors for Bitcoin who simply will not give up on the idea. There are warriors for Litecoin as well. Hodlers of last resort. A true attack to disrupt Bitcoin, or a "final attack" would have to come via the protocol level. This is just how I see it.
So, what's holding back the powers at be from engaging in a 51% attack? A number of things I will try to explain. Perhaps part of the people in positions of power don't want to regulate bitcoin and crypto. They see the good in it. I wanted to give at least some of them, the benefit of the doubt. This seems to be the minority at the moment however, because the SEC is coming hard as of late. Operation Chokepoint 2.0? If Bitcoin was the only cryptocurrency on the market I think they would. Attack it, not admit it, get it over with. A covert operation. This would ensure the powers at be will continue to issue fiat currencies for the next couple of decades or even centuries. Engage in CBDC's and have even more control of what you earn, how you spend, when you spend, and tax.
There is a massive problem for the people who want to attack Bitcoin. It's called, Litecoin.
Sure, you may be able to attack Bitcoin, dismantle it, and spend tons of money to carry out the attack. It's a huge IF. Problem is, even if you are successful, there are other currencies ready to take on the exact role that Bitcoin has today. Litecoin is primed to do so. And to be fair, things like: Bitcoin Cash, Monero, Dogecoin, DGB, even elements of ETH could in part take Bitcoin's role as the money for global citizens. Litecoin specifically is a source code of Bitcoin, and operates extremely similarly. That's why I think Litecoin would naturally take over if an attack on Bitcoin ever did occur. One can attack BTC, but LTC still exists, ready and waiting. Ok, so kill Bitcoin, then kill Litecoin, then kill DGB, then kill a BTC/LTC fork, see it never stops. Since Bitcoin is open source a new Bitcoin is easily copied and created. The government would have to 51% ALL the Proof-of-Work coins all at once to truly attack crypto as a whole. Everyone would probably know who is doing it as well. Creating an identified attacker. Would the attacker really want to reveal themselves... And again, even if they do attack all the current POW coins on the market, a new POW coin could easily be spun up. This wold be a cat-mouse game where the attacker would get exhausted by continually trying to find the POW offspring. The mouse wins here. Bitcoin wins, Litecoin wins.
So going through this War Games exercise allows us to realize that attacking Bitcoin via a 51% attack is sort of useless. If they do, then Litecoin takes over. Or even Bitcoin (2) reorganizes and takes back the network effect. Miners would have a chance at finding the "honest" chain. Bitcoin has many passionate geniuses, if an attack like this were to ever commence, the Bitcoin protocol (and price) would surely be impacted but I think people would possibly fork and save the project. There are more layers to this than what I just came up with. But again, with the existence of Litecoin, it indicates to the attacker, that the attack could be futile. Litecoin offers safety to Bitcoin. Safety in numbers. A safety net.
Since Bitcoin was released as open-source, variations of Bitcoin can exist and it isn't a one and done process. If BTC was closed source and only Satoshi could reproduce the magic, Bitcoin and the overall idea of cryptocurrency could be demolished. Satoshi would have to re-emerge and release another Bitcoin. But it's not closed source, it's open source. You can't stop it. The genie has been let free. You can't cram it back in the bottle. All these other coins, protect Bitcoin from being 51% attacked as attacking Bitcoin would be a nearly pointless exercise. It would be like trying to kill all cars by killing the most popular car company. Other companies exist and would gladly take on the #1 role. There are few winning options to attack BTC, so I speculate that its attack will not come via the protocol level of a 51% attack. Litecoin and others serve as a safety net. You cut off the head, but two other heads grow in strength and size, and the original head regenerates. Satoshi was/is a genius.
Moving beyond this idea of 51% attack, Litecoin is primed to take on whatever roll Bitcoin can't or doesn't want to focus on. Spending, security, privacy, transaction costs, mining, and other technologies that Bitcoin may not want to embrace for whatever reason, Litecoin can consider them. The fact that Litecoin has fungibility and privacy through MWEB before Bitcoin does, is an extremely good sign about the power of Litecoin. Regardless of your opinion on Ordinals, Litecoin can be the yin to Bitcoin's yang. If Bitcoin is too aggressive, Litecoin can be passive. If Bitcoin is too passive, Litecoin can be aggressive. Litecoin can counter any of Bitcoin's missteps and poor decisions. Exciting times are ahead for Bitcoin and Litecoin.