First, it's obvious that you're only starting this because you're jealous of the DS numbers, for whatever reason. The difference between DS, DSlite, DSi and DSiXL is nil, when it comes to the games. Apart from a handful of downloadable minigames, every single DS cartridge plays in every DS iteration, and exactly the same too. And, man, you are fully aware of that.
Second, I don't think that many people own "each and every single one of them", why on earth should they be that dumb? I don't personally know anybody who owns more than one. Yeah, there will be some, but then there will be some who replaced their PS2 phat with a PS2 slim or their 360 fat by a 360 slim and so on.
You post is annoying because you are being hypocritical. You pretend not to know which iterations DS has had ("and maybe a couple models in between that i missed."), and you pretend not to be aware that the 3DS is a completely new system. If you don't even care enough for the DS to look up the facts, why start a thread about it?