You're right that this is potentially anticompetitive, but
“Companies will regulate themselves” is a cute libertarian bedtime story.
I've never heard libertarians say that. Rather, they say that consumers have the potential to regulate companies if they choose to do so, by voting with their feet. We should do so more often than we do; when there's a free market (monopolies are not free markets) it feels pretty good to tell a company to go screw themselves.
Personally I switched back to Firefox when Chrome tried to force login to my Google account, and I haven't missed a thing (other than some dev tools, e.g. websocket inspection). Firefox Quantum is really good, and their bookmark sync has replaced my previous usage of the now-defunct Xmarks.
“Companies will regulate themselves” is libertarian orthodoxy, and suggesting otherwise is ahistorical and silly. (But then again so is libertarianism.)
Personally I switched back to Firefox when Chrome tried to force login to my Google account, and I haven't missed a thing (other than some dev tools, e.g. websocket inspection). Firefox Quantum is really good, and their bookmark sync has replaced my previous usage of the now-defunct Xmarks.