That’d certainly be a good feature, but it feels to me like it’s a fairly niche need. And as per that post, it’s also a big technical effort. I can see why there isn’t anything in the way of development updates.
That is me being a bit of an apologist for Firefox though. If you consider Firefox unusable because of that, then that’s a pretty valid frustration.
Still, I’d encourage you to try and find a way to make it work for you because Chrome is evil.
They can be slow to adopt changes. I think the Mozilla foundation getting more funding, staffing, and refocusing on their browser would be the better solution.
While Chromium is an open source project, it is still developed and maintained by Google. For something as important as a web browser, I think it’s imperative that there’s an option outside of their control.