This is part of why web standards processes need to be very conservative about what's added to the web, and part of why a small vocal contingent of web people are angry that Google keeps adding all sorts of weird stuff to the platform. Useful weird stuff, but regardless.
1. not trillion dollar tech companies
or
2. not 99% funded from a trillion dollar tech company.
I have long suspected that Google gives so much money to Mozilla both for the default search option, but also for massive indirect control to deliberately cripple Mozilla in insidious ways to massively reduce Firefox's marketshare. And I have long predicted that Google is going to make the rate of change needed in web standards so high that orgs like Mozilla can't keep up and then implode/become unusable.
Arguably, we could lighten the load on all three teams (especially the under-resourced Firefox and Safari teams) by slowing the pace of new APIs and platform features. This would also ease development of browsers by new teams, like Servo or Ladybird. But this seems to be an unpopular stance because people really (for good reason) want the web platform to have every pet feature they're an advocate for. Most people don't have the perspective necessary to see why a slower pace may be necessary.