The following is my opinion.
1) I don't like 99% of mature games or R movies. Seeing people dismembered, tortured, sex scenes, or any combination thereof is not why I play video games. Many PlayStation games fall into these categories. There are exceptions, but they haven't been enough to justify the expense of buying a PlayStation.
2) For my kid/teen years, I loved my GameCube dearly. It was the console me and my friends played every day. None of us had any time for PS2's because all our gaming time was spent going back and forth between Smash Melee, Mario Party, Star Wars Clone Wats, Rogue Squadron 2, and the hordes of other games on the purple box. That is, to this day, my single favorite gaming console ever, so PlayStation didn't really stand a chance of winning over my time back then. I certainly couldn't afford two devices then and since we all were playing GC like crazy that furthered me not buying one. Then PS3 came out with an absurdly high price point and that was extremely off-putting and I loved GameCube so much that I got a Wii.
3) I have never liked the PS controller design. It's always felt weird in my hands, unlike the perfect gaming controller that is the GameCube which felt more comfortable in my hand than any other controller.
4) The fanboy impact. When I was younger I encountered a lot of kids who owned PlayStations and had a rather arrogant mindset because of it. They'd always brag about how much better the PS was compared to Nintendo, kind of like Apple fanatics we're just as insulting in high school. That rubbed me the wrong way. Should I hate on a company for what their consumers do? No, but I was a dumb kid myself lol.
The ps2 era couldn't end soon enough. Sony being that far ahead with sales was awful. It's nice to know nintendo has won the last two console generations against them and restored order.