I don't agree with you. You can buy a fraction of a bitcoin, so if you can only afford $100 of BTC, then buy $100 of BTC if you believe in the crypto.
Alt coins, in my opinion, try to solve an issue that BTC cannot do or is to expensive to do. Healthy competition is also great.
I honestly still cannot believe that after all these years,,, people still believe in this "BTC is too expensive to buy nonsense". Ok, fine, yes if you want to buy tiny amounts lower than $100 it is quite difficult to find exchanges who will do this without charging you crazy fees to withdraw BUT it is still possible with P2P.
Altcoins the costs are actually the same when people realize it. Slippage is horror.