>> This may sound melodramatic...
Yeah. A bit.
Thing is, Blink is not Chromium, Chromium is not Chrome, neither of them is Google, and BSD-3-clause is a pretty damn solid bulwark against the monopolization of the "control of fundamental online infrastructure", were that to ever become a concern again.
And the other bit is that the building blocks that make up Chromium power a lot of technology that is totally independent of anything under Google's influence, including NodeJS, Cloudflare's Workers, Microsoft's VS Code, and Amazon's Firecracker. They use it because it's solid, well-engineered tech. And even though Google wrote it, Google can't control it or stop you from using it against them. Microsoft isn't ceding anything at all to Google, Google's not in control of anything here.
The uncomfortable truth is that the role of neither Gecko nor Firefox nor Mozilla is particularly critical in terms of protecting the free and open Internet. What prevents Google from going all IE6 with Chrome isn't Mozilla, it's Chromium. If IE had been a BSD-licensed open-source project since 1995, then all the BS we endured in 2002 could never have happened; explorerium would have been trivially forked to create a sensible competitor with no switching cost.
Google tied their own hands from the very beginning, and by ensuring Chromium doesn't lag behind, they're keeping their hands tied. Almost as if they were doing it on purpose. In fact, the fact that Microsoft is switching to Chromium locks both tech giants into an intriguing sort of bargain. Each can benefit from the other's work as long as neither strays too far from the open source codebase, as long as they both push their changes into the open. So you end up with a reasonable guarantee that the future of the Internet stays independent; not because of a nonprofit competitor with a strongly-worded manifesto, but because none of the the main players can afford to make it closed.