Until now bitcoin is still in control of the market, but I'm not sure that bitcoin will forever control the market. Now I see bitcoin price movements very slowly, there are actually some coins that I see the price movements start fast. One of them is altcoin, for that I predicts that there is a possibility in the future altcoin will be able to control the market and beat bitcoin.
I think As long as the system has to buy altcoin using bitcoin / eth, it is very unlikely altcoin will go beyond bitcoin, because there will be people who put as much money into BTC as they do.
It is an interesting opinion that I doubt many people in this forum share. Altcoin is generally just a bigger market, but for the most part, bitcoin is the bridge between them. Generally, if you want to buy altcoin, you should buy bitcoin and then use the bitcoin to buy alts. It's hard to find a place to buy altcoin directly. I believe this is what makes Bitcoin and Ethereum particularly so great in terms of all other altcoins.