What are the reasons you are bearish on the future of crypto?

So recently optimism and FOMO came back and rightfully so. Bullish posts are everywhere, but now I'm addressing the pessimists in this sub, people that aren't convinced crypto will have a bright future.

In the short term, nobody knows a thing about what direction will the prices go, but we can always collect information for a fundamental analysis of crypto as an asset class. I tend to always be bullish on crypto and to estimate its pros more than its cons. I see this investment as the only possibility to buy a house without taking a life-long loan. I understand that I have to be more realistic in my evaluations, so I would like to know what you particularly dislike about crypto and if you think that those flaws will prevent mass adoption.

When answering, try to think about Bitcoin, Ethereum and the most important projects, because I think that lower-cap coins are too unpredictable and need more time around to be really evaluated.

I think that talking about reasons against your thesis helps you to better understand the argument and be a better investor, so thank you for your answers!