If people think that making an ETH ETF could make bitcoin go down in the rankings, they are expecting way too much from ETF and they are expecting way too much from ETH as well. Its clear that we are going to end up with a result that will be not that easy to handle, and it will be quite good for all of us as well. We should just focus on what we have, and not have some grand imagination about what could possibly happen.
We could also see dogecoin reaching 20 trillion dollar market cap, in reality there is no technical aspect of it that would prevent that so it is possible, but its as much possible as me waking up to a million dollars in my crypto account, won't happen. So that is why instead of looking at what's possible, lets look at what's probable.
Crypto is not only about ETFs. It's way much more. It's a movement. A means to obtain true financial freedom and self-sovereignity. Bitcoin started it all, so don't expect it to lose its position anytime soon. Ethereum wouldn't had been nothing without it. What was the OP thinking? Set yourself forward 10 years from now, and BTC will still be the #1 cryptocurrency in the world.
Believe me, things are going to get worse for ETH as centralization grows within the network. The ETFs will gather a massive influx of capital, though. But who cares about the money, if the project will move away from crypto/Blockchain tech's core principles? With "Wall Street" in the game, the market will become more centralized than ever. At least, "hodlers" will be happy.
