Open source or not, chromium is still fundamentally chrome and backed by Google, is it not? It can be used vanilla or built on top of (e.g., chromium and brave), but where Google goes so goes chromium. This is as much a privacy concern as it is a browser mono-culture concern, which has been a popular topic lately.
Further, just because something is open-source doesn't automatically free it of corporate encumbrance - something Google knows quite well [0][1].
The issue at hand is that Chrome may or may not perform surveillance or support it. If that is the concern, with Chromium you get to see everything it does and you know the code you're running, like any other open source project. So I disagree that using Chromium is a privacy concern similar to using Chrome.
Browser monoculture has advantages and disadvantages and would be the topic of a separate discussion.
I never claimed that Chromium is free of "corporate encumbrance" nor do I think that's a problem. I don't think there's any realistic risk that if Google stops developing on Chromium we would be losing that browser, there's too many people outside of Google with invested interest in keeping Chromium going so a popular separately maintained fork seems likely. And even in the extremely unlikely case that Chromium disappears overnight and nobody wants to touch that code base ever again, there are other browsers out there.
Further, just because something is open-source doesn't automatically free it of corporate encumbrance - something Google knows quite well [0][1].
[0] https://boingboing.net/2019/05/29/hoarding-software-freedom.... [1]https://boingboing.net/2019/04/03/i-hate-being-right-2.html