I can only speak for myself, but I don't know that Nintendo changed, but rather that they didn't really evolve their focus as gamers grew older. There is nothing wrong with that, it just means some people moved on.
My first gaming system was an Atari 2600 that my father bought for my sisters but which I soon took over. The first system I paid for myself, though, was the NES, which took all of my birthday and Christmas savings. I followed that up with the SNES. I was solidly a Nintendo fanboy, ordered the magazine and everything.
But I was growing up, my tastes were changing, and quite honestly, I got bored with platformers. Pretty EVERYTHING was a platformer back then. Then I stumbled onto Final Fantasy 3 (J6) and it blew me away. It was, quite honestly, the most important moment in gaming for me. Unfortunately, though, experiences like that were few and far between on Nintendo consoles.
The reason I'm giving all that background is to provide context for what came next--Final Fantasy 7. I still, to this day, remember when I first saw the commercial on television. The Playstation won me in that single moment. Suddenly Nintendo was a part of my childhood and seemed kind of boring and predictable. Nintendo games are fine for what they are, but I had the impression that Nintendo was satisfied with what they were doing and had no intention of going after straying gamers. Rather, their stance was that they were at the top so gamers had to come to them. Perhaps it wasn't arrogance but it sure felt like it.
The variety of the PS2 cemented my break with Nintendo. Variety is what I wanted then, and still want. Sure, I still miss Zelda, but it just didn't feel like Nintendo cared if they had my business or not. They're very centered on their own formulas and pathways, which is fine. It just so happened that I could find more and different experiences elsewhere which better suited my changing tastes.
