Personally I think just leave it to users to vote with their feet. If I think a site is too slow to load or too slow to use, I'll stop using it. If I'm happy to wait for 10Mb of js to run a web app, then let me.
It used to be innocuous when Google had 20% browser market share, but now they act like they own how users should experience the web. Like the uBlock origin guy said... if Chromium keeps heading down this path it should no longer be called a "user-agent" because it's no longer acting on behalf of users.
There are plenty of reasons why you might want to heavy apps or raw photos on the web. This is the beauty of the web, freedom!