In January this year, a lot of independent YouTubers, unrelated to private equity and cars, also quit:
https://www.theverge.com/2024/1/20/24044533/mkbhd-weighs-in-...
The car YouTubers are just a little behind the curve.
There was a pandemic bubble in 2020 - 2021 where ad spending on video was huge, tech companies increased their headcount substantially, and creators were riding high. Twitch and YouTube were dropping eight-figure exclusive contracts left and right. Those days are over, the money isn't there anymore, and we are seeing the tail end.