My most positive but realistic prediction: Bitcoin is gonna stay around as a pump-and-dump scheme to make the rich richer. Other cryptocurrencies will slowly fade away including (as one of the latest) ETH. They are not suitable as a currency and are more of a ~~gambling~~ investment opportunity. Per default, most cryptocurrencies are a privacy nightmare, especially Bitcoin.
There are exceptions. XMR is fairly stable in value and is actually really close to what many people want: cash but digital. If GNU Taler takes off, there's will be a more comfortable option for paying while retaining privacy, making XMR more obscure.
I assume laws and the state will also have an influence, especially with the climate catastrophe questioning the immense amount of energy necessary to run all of this. Even if crypto were more efficient if it replaced fiat, it's not gonna happen. There's hard power preventing it. Both at the same time is reckless when there are people dying.
Also money sucks in general so best case scenario it gets thrown onto the trash of history.

inb4 crypto shills: Remember that there are people whose income and investments depend on people believing bitcoin is more than gambling.