First and second tier websites already switched it on long ago. Because in China we had an ancient tradition for ISPs to sniff and modify user's traffic to (for example) inject their own affiliation codes to the web request. Those websites hates it of course.
Given Chinese govt has been controlling some CAs, China vs. HTTPS irony is.. well, less of an irony :)
And of course, in the context of CA, what's truly important is transparency in the audit process and continuous monitoring. Catch them red handed will end their business[0] once and for all. And so far, most of them are rule-abiding.
[0] https://blog.mozilla.org/security/2016/10/24/distrusting-new...