Many argue that one of the altcoins can probably in the future beat Bitcoin and be number 1 in CoinMarketCap. I believe Bitcoin will be never beaten by any altcoin, especially centralized one, because Bitcoin is decentralized, is the first crypto currency created, and worshipers of Bitcoin will increase over the time.
If another Bull run happens, Media will only talk and focus on Bitcoin, new comers in crypto will learn about Bitcoin first and foremost.
I believe in crypto. But I worship Bitcoin. And all the coming bull runs will be led by Bitcoin.
Bitcoin was the first and here to stay the first, if Jp Morgan coin will not put billions into their token and beat the marketcap

Otherwise, bitcoin will be the most liquid, capitalized and most trusted in crypto space. First is always first.
Who knows. Well probably you're right for the next couple of years but it's not impossible that another crypto may take btc's place. It may be one of the top coins in cmc or probably it hasn't been conceived yet as of now. The only thing that's for sure is that anything can happen in crypto even if it's as massive as changing of the top coin.