Hardly niche. My laptop isn't new and it has hardware AV1 decoding and encoding. My 10 year old iPhone 7 can play 1080p AV1 video in software for over 200 minutes with VLC. The iPhone 7 was released in 2016, a year and a half before AV1. The dav1d decoder is mighty.
Supported is different from doing it well though. You do notice the performance hit even on TVs that playback YouTube videos on AV1.
Even on 1080p videos running on AV1 on 1x, the TV system bogs down and any kind of interaction has a variable 1-3s lag. On some TVs if you do 1.25x the TV automatically "downgrades" the resolution to 480p to avoid dropping frames.
I wish there was an option to still use VP9 / H.264 on those systems (even limited to 1080p).
My TV lags out even when doing nothing. So I use it as a dumb panel and let another device handle the streaming and decoding. Also has the benefit of blocking LG from loading adverts all over the UI.
Yeah I could imagine the AV1 codec sticking around for a very long while, even as a fallback for AV2. There's still hundreds of millions of people out there using old/cheap devices (especially in developing countries) where that battery drain from software decoding is a big problem, so AV2 would be nonviable.
Some of the early use of VP9 and AV1 was Netflix serving video to people in developing countries. Their metered bandwidth was more of a bottleneck than the CPU playback.
Netflix uses AV1: https://netflixtechblog.com/av1-now-powering-30-of-netflix-s...
YouTube uses AV1. It's tough to be more mainstream than that.
Right click on a YouTube video and select Stats for Nerds. If your system is capable of it, chances are it will be playing back in AV1.
Most of the YouTube videos I watch these days are AV1 encodes. Sometimes it's in VP9 and occasionally it's H.264.