We ought to just stop using HEVC collectively, the bizarre licensing scheme they've set up is just not worth it, and AV1 allows for better compression anyway.
H.265 took many years to gain traction, precisely because h.264 hardware decoding was widespread but h.265 hardware decoding wasn't.
Codecs simply don't take off in a big way until the hardware decoding becomes widespread. And video sites will maintain dual streams for many years, to continue supporting older hardware.
If my memory are correct at the end of 2020 90%+ of all online video were still on H.264. We are still pretty much H.264 only simply because it is good enough for most things.