be careful what you believe specially when it comes to the lies that the "top altcoins" tell you
Top altcoins are not all from their marketcaps. There are adoption, use cases, and communities behind any project. All of these elements build up an ecosystem of one project.
I don't believe that any altcoins can be better than bitcoin if combine all of elements. It is more sucked if expand it to top 100 altcoins.
Even in the top 10, Tether USD (USDT) has many drama recent years and I don't know when they will be sucked like XRP, DASH, Monero, etc. As there are many other available stable coins (USDC, DAI, etc.) the drama on USDT is possible and it can make a shock on the market but long run, the market will be fine with or without the USDT. There are alternative stable coins.