A lot of the governance structures with "foundation" in their name, e.g. Apache Foundation, Linux Foundation, Rust Foundation, involve some combination of corporate parties, maintainers, independent contributors without any singularly corporate heavy hand responsible for their momentum.

I don't know that road maps are any more or less "community driven" than anything else given the nature of their structures, but one can draw a distinction between them and the degree of corporate alignment like React (Facebook), Swift (Apple).

I'm agreeable enough to your characterization of open source projects. It's broad but, I think, charitably interpreted, true enough. But I think you can look at the range of projects and see ones that are multi stakeholder vs those with consolidated control and their degree of alignment with specific corporate missions.

When Google tries to, or is able to, muscle through Manifest v3, or FLoC or AMP, it's not trying to model benevolent actor standing on open source principles.

My argument is that "open source principles" do not suggest anything about how the maintainers have to handle input from users.

Open source principles have to do with the source being available and users being able to access/use/modify the source. Chrome is an open source project.

To try to expand "open source principles" to suggest that if the guiding entity is a corporation and they have a heavy hand in how they steer their own project, they're not meeting those principles, is just incorrect.

The average open source project is run by a person or group with a set of goals/intentions for the project, and they make decisions about the project based on those goals. That includes sometimes taking input from users and sometimes ignoring it.

Chromium can be forked (probably there are already a bunch of degoogled ones) to keep Manifest v2

what's missing is social infrastructure to direct attention to this (and maybe it's missing because people are too dumb when it comes to adblockers, or they are not bothered that much, or ...)

and of course, also maintaining a fork that does the usual convenience features/services that Google couples to Chrome is hard and obviously this has antitrust implications, but nowadays not enough people care about this either