Xi's thinking behind cracking down the after-school education sector started from 2018, he published an essay on this issue. From 2018, the ministry of education has been issuing orders to reduce the study pressure of school kids [1]. Chinese government set an objective, a few policies will lay out to achieve it, the current crackdown is just a follow-up when ministry of education's policy didn't work out, now four ministries are working together on this objective.

[1] http://www.moe.gov.cn/srcsite/A06/s3321/201802/t20180226_327...