“WASHINGTON (AP) — A judge on Monday ruled that Google’s ubiquitous search engine has been illegally exploiting its dominance to squash competition and stifle innovation in a seismic decision that could shake up the internet and hobble one of the world’s best-known companies…”
I think the main problem is that Chromium still contributes towards the browser engine monoculture, as it is bug-for-bug compatible with Chrome. Therefore if you switch to Chromium, it’s still enough for the web sites to test for Chrome compatibility, which they will, because it has the largest market share. Users of competing browsers suffer, further driving the lure of Chrome (or Chromium).
On the other hand, if people switched to some other engine, one that does not share the same core engine or even the same history, this will no longer hold: web sites would need to be developed against the spec, or at least against all the browsers they might realistically expect their customers to use.