China has made for-profit extracurricular tutoring illegal since 2021. [1] Of course there can be under the table operations and discussion to be had about regionally biased gaokao difficulty, but I think it's worth recognizing gaokao being a real chance for upward class mobility, hence why it is so competitive.
Oh so that explains it!
Starting in 2020 when I was a new professor, I was contacted by a company that works with Chinese families to tutor their students directly. I would be paid $400 an hour to teach them online remotely.
Originally I thought it was because of COVID lockdowns and that may be part of it.
But the opportunities have continued since then. I stopped doing it as my career has become more involved but I still get solicitations from time to time, so it must be because of what you say.