You have no idea how much truth is actually hidden in your sarcasm.
It's not that Smash fans don't try the series that get in. There's a reason for that, whether it's age, financial restrictions, or interest. But one thing the fanbase is notorious for, at least the character speculation side of the fanbase, is that most of the fans are folks who grew up on Nintendo and haven't branched out. Around the time of Brawl, I was one of those people who had no idea who Snake was, and wanted Sonic because he was...well, Sonic. Add onto that the fact that he was on Gamecube pretty frequently...
The roster becomes waaaay more special when you have actually played a bit of everything. It's the reason I played Zelda, Metroid, Metal Gear, F-Zero, Castlevania, Earthbound, Kid Icarus Uprising, more Kirby, Persona, Final Fantasy, Street Fighter, Fire Emblem...pretty much most of the roster. Granted, I don't spend my money on much else aside from financial obligations, and...games and comics. That's about it.
As I always say, if you want to try out a new series you haven't played before, it's super worth it. Pretty much most if not all series with playable characters in Smash are worthwhile to play for one reason or another.