I keep IPv4 off on a media computer all the time out of curiosity. IPv6-only is still unusable because only about 5% to 10% of top sites that I find during a Google Search work. It's almost guaranteed that a website will not load on all the top results.

So even if it's true 50% of clients support IPv6, only about 5% to 10% of website hosts do.

Sure a person can do a dual-stack setup or do some IPv4-IPv6 translation, but seriously IPv6-only should be plug-and-play by now.

Cloud providers and hosters seem to have the least interest in implementing IPv6. Sitting on a huge supply of IPv4 addresses gives them a competitive advantage. So they try to disable IPv6 as a default.