As I wrote in the OP, I think everything depends on the kind of adoption we'll see in the coming years. If Bitcoin isn't able to convince the world that it has real value, and only remains an asset people buy to "make money" and get rich fast, then a super bear market is completely possible.
This has been my fear for a long time - if most of Bitcoin's value come from "buying it to sell later", then sooner or later it will crash very hard until its value mostly will reflect its utility.
I guess that in this case Ethereum could surpass Bitcoin as leading cryptocurrency for a while, because its smart contract model is rooted deeper in "real economy" due to the usage to crowdfund tech companies.
Ethereum is far worse than BTC due to its high centralization, and its utility is actually fake, because it just provides crowdfunding and marketplace for more useless tokens.
Such a super bear market could however also be an opportunity: if the speculative capital is driven out, but Bitcoin's USPs remain uncontested (uncensorable, borderless digital money), then the supercycle could even materialize after a super bear market with prices of let's say <$5000. Basically that would be similar to the dot-com/tech bubble, which lasted a little bit less than 10 years until it popped (early 90s to 2000/2001), followed by a depression but then sustainable growth after 2009/2010 when the business models that were still an illusion in the 90s and early 2000s finally began to work.
The difference between crypto and dotcom is that the Internet technology was making constant and fast progress every year, while crypto has been stagnant for a long time. Bitcoin is not too different from Bitcoin of 10 years ago, and altcoins just invent new ways to sell premined tokens with no real use - DeFi, NFT, ICO and so on is essentially the same.