ASIC are used for major cryptos like Bitcoin that can justify the design and fabrication costs. For random shitcoins, you need GPUs.
There're cryptocoins other than BTC. Ethereum and Monero are two that are popular and GPU profitable.
Aren't all their prices pretty correlated though? When Bitcoin falls like this, the altcoins do too.
Even if there were a fixed peg between cryptocurrencies, that still wouldn't imply that GPU-mining BTC is just as good as GPU-mining other cryptocurrencies.