Yes, but AV1 hardware encoding beats x264 software encoding, if thats the only other option (albeit not by much).
x265 should be what is compared against AV1 when discussing quality and encode speeds.
We use x264 for compatibility purposes, if your device is intended to play video, it will decode x264. x265 decoders are in a lot of devices at this point, and AV1 is just now starting to see representation.
x264 is like .jpeg and will probably never die.
It will probably eventually be like mp3, where users are still reflexively encoding to it without a good reason.
Netflix also uses H.265/AV1. Amazon, HBO, Disney, etc also use H.265, but I believe only on higher resolutions.
On Apple world even phone pics uses HEVC (HEIC).
I think it's a total mix honestly (Because tiktok/X/Meta uses h264 as far I know).
More technically correctly, more than half the currently in use devices in the world do not support more than H.264
Like all my Smart TVs, my kitchen iMac, my parents’ phones etc. only my phone and my laptop support HEVC.
Netflix uses AV1 when on mobile data, even if the HW doesn't support as well (for TVs, it need HW decoding).
The only way to not use VP9 on Youtube is if you don't have the codec installed, which is super rare because the codec is open.
https://giannirosato.com/blog/post/nvenc-v-qsv/
x264 used the medium 10 bit preset, which is a bit of an oddball because 10 bit AVC is "unofficial," and many hardware decoders don't support it.