Usually we're taught to think of monopolies as a bad thing. "They stifle competition and lead to creative torpor!" people shout, and everyone nods sagely in agreement, secretly thinking, "Hmm yes - what does torpor mean?" But this is not always the case.
Let's be honest here, between 1995 and 2002-ish, PlayStation had a stranglehold on the console business. It utterly dominated the industry, destroying Sega as a hardware manufacturer and knocking Nintendo right off its perch as the accepted gaming overlord. This was a period where there were no smartphones, no global indie community to speak of, and in which Japan dominated software production. All of these factors combined to create a stable, yet wonderfully experimental era in game design. I have given it a catchy, highly academic name: 'the era in which weird Japanese games went batshit mainstream'.