Whoever. Whatever. OSS is a system for finding the most capable entity in the world at developing a software capability and letting them get on with it. It'll find someone to pick up the slack if Google starts doing a terrible job. In this world of 8 billion humans and however many thousands of companies, there'll be one who knows how to put a web browser together.
If I were going to guess today it'd be brave.com, but the world is large and competitive.
This is very handwave-y and idealistic. Sure, 8 billion humans, and thousands of companies on a cosmic timeline will lift the "most capable entity" to the top, but the road there is going to be extremely long if you just "nah they'll get it" and not do anything else.
I named a specific company, pointed out a specific example of the dynamic featuring GCC and Debian is just one iceberg in the OSS ocean demonstrating that there are more than 30,000 packages built on the principle that free software is better than closed source.
I'm not sure how much more specific and concrete you want the argument to get, but that seems fine to me. The market is big, people care about this part of it. There will be a sponsor for the work if Google isn't up to the challenge.
The only reason everyone uses Chrome is it is really good at what it does and to date Google has been a high quality steward.
I think that's a tad idealistic, though. You'd need the resources to keep fighting against the constant changes and ever diverging codebase the more Google goes it's own way. And already has been doing it slowly.
Also, Mozilla and Apple have been important for keeping privacy relevant every time Google have tried to push for some privacy eroding web standards.
Edit: I agree with the sentiment though but I just trust the current situation more.
> You'd need the resources to keep fighting against the constant changes and ever diverging codebase
Assuming that Google is making Chromium better, sure. If they are making it worse then not keeping up with the changes is an advantage of the fork.
If Google starts making changes that reduce the value of the codebase, then a hard fork immediately becomes viable. If they are good custodians even a totally separate codebase isn't enough, it'll end up in the same position as Firefox - marginalised.
If I were going to guess today it'd be brave.com, but the world is large and competitive.