That wasn't really part of the problem. The most used browser engines are often some of the most irritating and frustrating to deal with, just look at Internet Explorer for most of its existence. Safari is an obnoxiously widely used browser because Apple enforces its use on iPhone no matter the browser you use and it has a bizarre update schedule tied to OS version. This causes many iPhones to have ancient versions of Safari.

The problem here is not that there are or were too many browser engines, it is big companies making their browser engines in anticompetitive ways.

We're "lucky" that Blink, the engine that runs all Chromium-based browsers, is currently keeping up with browser standards. For now. Who knows if Google will keep it that way or decide to change course and move away from FOSS standards.

It is dangerous to put so much stock and power into a single huge corporation like this. A large variety of innovative and competing browser engines is far healthier than one dominant engine.