I guess it depends how you looked at it. Performance-wise AV1 seems more similar to h265. Hardware support wise h266 seems to have only had shipping hardware this year?

So I guess neither of these line up 1:1. I tend to see h265 and AV1 competing pretty hard right now so I tend to think of those as one generation and presumably h266 and AV2 will compete as the next generation.

The way MPEG runs things there are some oddness with the likes of H265. MPEG likes to add little extensions to a codec over time. That's why H265 was first released in 2013 but ultimately had like 10 different extensions after that fact (the last one in 2024).

AV1 and VP9/VP8 before that have, in contrast, been pretty much static after they were released. AV1 has had a single errata after it's release.

So I could see why you'd see H265 as the competitor. I mostly don't simply because I believe they explicitly stated that they were trying to be competitive with 266.

I personally prefer the way AOMedia is running things and I suspect hardware manufacturers do as well. No licenses and AOM is creating open source reference encoders/decoders. They are working very hard to make it easy for manufacturers to be able to pick up the spec and run with it. Keeping the stream standard static for a long period also means manufacturers don't have to worry that they won't get a new extension next year. Content encoders are also reasonably guaranteed that their encoding with today's software still works with yesteryear hardware.

MPEG, on the other hand, is paywalling the crap out of everything.