"We" could do that now. "We" haven't because it's not profitable to do so, and there's barely enough oxygen as it is for one non-profit browser funded by donations (Firefox).
If only Firefox were funded by donations!
If it was that easy we would have it already.
ungoogled-chromium?
That is only half of the statement I was replying to.
You missed
> I’d imagine that would quickly become one of the most used browsers
It doesn't need to be one. And even if it was, we'd never know as it doesn't have any built-in telemetry and doesn't use a custom useragent.