OP was arguing that it was decreasing. Steam is a bad source of info for a lot of reasons. Meta is the largest platform and they don't release numbers. My personal feeling (Apple Vision Pro hype not withstanding) as a VR developer is that the industry is in the slow growth phase and will continue to grow as real usecases are found and hardware continues to improve year over year.
Sure, the source isn't perfect but May 2021 still being higher than this peak is no more an argument it's actually growing in absence of other actual data nearly 10 years into the current cycle. Particularly since this is for the much more popular overall VR market, not just AR. That could always change in the future, but there is nothing beyond hopes and feelings suggesting it's already changing at the moment (not that those can't ever turn out to be right).
Typically anything in ${latest-steam-survey} is more unreliable than ${not-latest-steam-survey}. People often get hyped up on a big month change in e.g. Linux that ends up being a detection issue or the like.