Why buy a Gamecube when you already had a PS2?

In the end I think it was just luck vs a lack of 'violent' games.

we all know violence sells, and Super Mario Sunshine, although an awesome game, really doesn't get the Testeronnie going.

That said.

I love most of my gamecube games, and am grateful the wii is backwards compatible with it.

If you have a wii and never had a gamecube, do yourself a favor and grab Super Mario Sunshine!

And the fact that Nintendo demoed the GameCube with the Wavebird which you had to buy separately.

For Mario, Zelda, Smash, Fire Emblem, Animal Crossing, Resident Evil?

Of course, if none of this interest you, then there is no need for a Gamecube.

Maybe because it targeted kid and all the kids left (well most of them) left after the N64 no one I knew had a GC and only had or majority of mature games

The Gamecube had an image problem. It had no unique or discernible selling points of it's own and carried over from the N64 the image that Nintendo was just for the kiddies.