Even though the JS ecosystem has high churn there are many many existing websites that were made years ago that continue to exist and that the browser makers don’t want to break for their users.
That is why I say both editions must be supported. The old and the new. But the thing is put a deprecated warning to the old so is possible to build a better new. This also will help to clean JS/CSS.
If this is true then almost all of them will update to https and almost none of them would bother otherwise.
So I guess the question is not if its ok for chrome to break the web for half the world its if its ok for chrome to impose this cost on site owners on behalf of users for the benefit of users.
Incidentally while there may be a lot of tiny sites that don't use https aprox 3/4 of page loads are already over https. Making myrandomhomepageaboutcats.com switch to https seems a reasonable cost for making the rest of the web more secure.