Eh, I wouldn’t go about ‘the self-hosted admins didn’t do anything!’. There never really was a time when the majority (or even a meaningiful minority) of users hosted their own email.

In the beginning, you got your email address from your school or your ISP, and it changed whenever you left/changed providers, so the initial “free” email came from the likes of Hotmail (which rapidly became Microsoft), Yahoo (which was uh, Yahoo), and offerings from the big ISPs of the era, like AOL and whatnot.

You still had school and ISP email, but it just rapidly fell out of fashion because your Hotmail/Yahoo/AOL email never changed regardless of what ISP you used or whatever, so it was legitimately a better solution.

And then Google came along with Gmail and it was so much better than every other offering that they effectively ate the whole damn market by default because all the people who were providing the free webmail at that time didn’t do a damn thing to improve until after Google had already “won”.

So if you want to be mad, this is firmly Microsoft and Yahoo’s fault for being lazy fucks.