For a while while Google had a minority and everyone was still targeting IE instead of the standard, they would detect that and take a different rendering path even if it meant preserving broken behavior. At the same time they tried to fix/improve the spec and wage a publicity campaign against Microsoft for not following standards.

While that’s not necessarily a capability a smaller not well funded browser might have, certainly they have lots of forums to advertise “hey Google is doing this incorrect thing, this is how we detect existing sites relying on that buggy behavior, and this is how you fix it”. You could even show a banner while browsing “standard confirming vs not”. You leave that banner out for places the standard is underspecified to be fair and reinstitute it once you’ve got it clarified, assuming websites are still relying on those nonstandard paths / Chrome isn’t addressing the behavior.

That being said, it’s no surprise this is the situation when all commercial investment into browser tech is by commercial companies giving it away for free. Think about the hundreds of millions of dollars being pored in. That’s not out of the goodness of their heart and it’s going to be difficult to impossible for anyone else to compete.

For what it’s worth I think a huge regulatory improvement to monopoly laws would be an anti-dumping provisions for software. You’re not allowed to sell something below what it costs you to make (including accounting for R&D) and the only person’s effort your allowed to 0-rate is your own and any unpaid volunteers you convince to join you. It would mean that browsers would now cost actual money that could fund third party efforts (ie if my budget for browsers is X then maybe I want to invest in a browser that treats me better). Of course the challenge with this model is that it makes it hard to actually enforce. Are you giving a feature away for free or are you improving an existing product and it’s part of that overall cost? How do you budget recurring revenues for products that want to amortize the cost over periodic payments instead of upfront ones? Etc etc. I don’t necessarily know what the answers are. There may be none. But certainly Google’s control of the web comes from the fact that they’re poring in huge amounts of money to maintain a controlling interest over the thing that enables a good chunk of their revenue stream. It’s not as important to Apple and we see them not investing as heavily (it’s important for the product but it’s not intrinsically strategically as key hence the historic neglect). Same goes to Microsoft which ceded its spot in the internet ecosystem to Google back in the day.

Anyway, what I’m trying to say is that Google’s control won’t weaken because you cede to duplicate their particular implementation. Their control weakens when you can take away their market share and for a smaller entrant you want to replicate as much behavior verbatim as possible to lower friction for users. It doesn’t matter what the spec says. Aggressively prioritize what is important to customers and serve the market where Google is incapable of doing it. For example, memory usage is a trivial one to get them on. They’ve lost control of that beast and can’t figure out how to get better. Clobber them in the head over that failure. They can’t handle many simultaneous tabs. Make your browser work smoothly and without crashing or using terabytes of memory even if it’s handling 100k tabs. If I were to take on that endeavor, that’s how I would take on Google (and no, I wouldn’t use Blink as a starting point because you’re just picking up all the tech debt and you’re not going to do a better job than Google at trying to shovel shit away - you need to start greenfield like Chrome did and firefox and opera did for a time when they showed what a performance hog IE was and how it didn’t even have valuable features that people cares about). Similarly, ship the browser with adblock and actively fight websites that waste resources. Prioritize aggressively the user’s health and digital well being (meaningful privacy improvements by closing as many side channel data gathering techniques as possible) and respect the well being of the machine you’re running on.