But the reason why I and some people are actually thinking it wouldn’t be affected heavily like that is because of the influx of institutions buying bitcoin now, I don’t think this institutions are going to dump on bitcoin like when weak hands were doing before in the past to move to Altcoins I think they will be holding their bitcoin till the end and even buying more which signifies little hope for altcoin dominance increase.
The other reason is other investors are actually looking towards bitcoin as a safer investment than gambling their money on lots of Altcoins now, in the past bull run they were far less Altcoins in the market and there wasn’t so many pump and dump like we have today, so as to avoid putting in money into just any coin.
Whether institutions sell bitcoin or not is still a question mark because they enter the market with the same purpose as us, which is profit, nothing more. And none of them have claimed or committed not to sell bitcoins and make a profit.
In their eyes, bitcoin is more like a stock than gold, they do not see it as a safe haven. So I don't believe they will hold it like they hold gold.
Also, if you notice, institutions are also pouring a lot of ETH money. They are openly buying ETH in large amounts and this will happen to many other altcoins as well when the SEC approves ETFs for them. Simply because like I said, profit is what they want and they won't be stupid enough to ignore bigger opportunities like ETH when the government has acknowledged them. That is why I believe bitcoin dominance will decrease further.