This is not hypothetical, as we’ve lived through this before with Internet Explorer. The web didn’t get better from that. Open source is a big plus now of course, but it’s still backed by corporations that want us for our data to make money. It’s never going to be pretty.
We might have to live through another monopoly (or we could call it web-communism?) but I am 100% sure we are going to condemn Chromium some time later and work our way back to a free browser-world. It’s the circle of life.