It's always a surprise. Altcoins don't rank on the top of crypto market for too long, except ETH and BNB. So even if you invest in a top altcoin right now, it might be outside the top 10 on the next 2 years. Meanwhile, Bitcoin is 100% certain to be on top 1. It's not a hard decision to make.
I agree with you. Altcoins other than BNB and ETH will not be able to stay in the top 10 cmc for long. You can look at the history and I still remember there were a lot of old altcoins in the cmc top 10 that have fallen out of the top 30 and even the top 100. I will no longer buy altcoins that I think already have maximum market capitalization and it will be difficult to create new capitalization. Altcoins like Litecoin, XRP and ADA are altcoins that I will never buy again to invest in for now. But I'm sure this thinking will change. But this is my current choice.