Why does Mozilla even develop their own browser? There is inherently nothing wrong with everyone using Chromium as a foundation. Mozilla could use Chromium as renderer while still doing all the privacy preserving stuff they do. There is absolutely no correlation between the rendering engine and privacy. And they few interlinks (fingerprinting, etc.) can very likely be addressed through patches that are rebased over Chromium.

Firefox with its own renderer is dead anyway on iOS already, where everyone is forced into Webkit. It seems like a loosing battle to spend so much money on something that doesn't give the average user ANY benefit whatsoever. Yes, Chrome will be a monopoly, but Microsoft already bought into that monopoly. What's the point of fighting a loosing battle? Focus on integrating Chromium and make it into a rock solid privacy-first browser.