I think at least part of the reason for this is acknowledging that the web isn't much of a web any longer. You've got three or four vendors that serve the vast majority of all internet traffic. And it's not happenstance that those same vendors now control something which was originally meant to be democratic.

Most of this document reads to me like that's the problem they're trying to solve, not just chrome's huge marketshare, so simply not targeting it doesn't serve their purpose.

how is the web not democratic?

in real democracies the populists (facebook, tiktok, chrome) always win. because that's what the masses want