The word is so badly used here that I struggle to comment on the premise of the OP.
It's the most used engine by virtue of being the best, most dev friendly, most capable, most supported engine. There was no market assimilation, no buying other engines, no using an hardware or otherwise market advantage to push for it. Its success happened organically and in no way shape or form should be seen with the word monopoly in mind.
Also, the engine won't make a game look a certain way, devs do that, artists do that.