One thing to be cautious of when trying to count browser stats is that the recent releases of Firefox are pretty aggressive about blocking tracking scripts, such as those used by a site like statcounter.com uses to count up browser usage <https://gs.statcounter.com/faq#methodology>

I don't know how to solve that problem, since those two outcomes are at odds with one another, but wanted to raise awareness

I think the stats are showing that we really need debundling of the browser from the OS. I'd wadger that those stats pretty closely align with the percentage of android and IOS users, or in other words the stats are completely dominated by mobile browsers, where hardly anyone changes browsers.

I can't understand why we have not seen strong regulatory/antitrust action on this front considering the precedent with MS.

It's harder to get people to switch browsers nowadays. When Chrome first came out as a breath of fresh air (IE was IE, Firefox was better but a bit "heavy", Opera was... Opera), normal users would just nod and agree if you recommended a switch, and even as a power user, I only had to migrate a handful of extensions and behaviors over. At this point, browsers (particularly Chrome and Safari on their respective platforms) have ingrained themselves into their users daily routine. Things like bookmarks and some habits transfer pretty quickly, but casual users won't care enough about this (until they're impacted more).

This exists, it's called Ungoogled Chromium. Removing whatever misfeatures Google adds to Chrome is fairly straightforward.

The real danger to having a single codebase for the whole web is spec validation. Most web standards rely on two independent implementations. For newer technologies we could technically count WebKit and Blink as separate, but Gecko was providing an entirely separate codebase that isn't a fork of anything.

Remember how WebSQL was basically put out to pasture because it was just SQLite, warts and all, shoved inside the web sandbox? That's the sort of problem we'd rather avoid. Single-implementation standards tend to pick up bugs and misbehaviors from their implementation, since everyone winds up depending on implementation bugs rather than getting them fixed to match spec.

Why is Mozilla fubar? I'd argue it's much less work to get behind Mozilla than trying to maintain a chromium fork.

Firefox on mobile works great for me and has for years?