After Bcash, most people realized these forks were all just scams and nobody wanted to hold them. Each new fork had diminishing returns and eventually there wasn’t enough of an incentive to create more of them. It was more profitable to launch a new coin on Ethereum. As long as you pretended to have some kind of novel product attached to your token, you could raise millions of dollars in an ICO.

Bitcoin forks had the inconvenience of inheriting BTC’s history with a fairly distributed supply, but with altcoins you could just create them out of thin air and allocate most of the supply to the founders and other insiders.