Well it was following the "IE standards". The difference is only rhetoric to avoid antitrust. Google dominates the standards. Edge is Chromium, Mozilla is maintained in survival mode by Google.
> Chrome does, pretty religiously
I wouldn't call it "religious" when Chrome follows stuff Google wants and Mozilla/Apple don't want.
> there are a number of open source browsers based on Chrome
Based on Chromium, you mean? That's still dominated by Google.
But you're just putting yourself out on an increasingly brittle limb to defend native apps, which imo work against user interests.
Again, Chromium-based browsers don't count if their contribution to the codebase is marginal.
Then Google implements stuff that Apple and Mozilla disagree with, and devs still rely on it (e.g. web bluetooth). Not even mentioning that Mozilla is a joke kept alive by Google for antitrust reasons.
But even a Chromium based browser setting is better than some random app that could have been a web page.
Don't you think you are slightly underestimating the complexity of a browser that works with 99.9999% of webpages?