You must have been somewhat late to this gig then. I agree today there is not an awful lot in it but in the PS2 era it was worlds apart (primarily as the xbox was actually a service where the PS2 was a disparate collection of varying infrastructures), the early 360 era once PSN got started in earnest was still streets ahead and give or take PSN+ (something the others should have done years before) many would still argue XBL has the slight edge though the "playing games, messages and matchmaking" stuff, which is the backbone of the whole enterprise, for now at least, is all there. Where it goes from here is the subject of massive speculation however; MS is doing some interesting stuff whether the gaming types that made it what it is today agree with that statement of not, Sony is walking an odd path and there are even interesting things happening in the PC world.
The gamecube had a few fumblings here when the others were building up, the Wii had proper online play, the DS had online play -- Nintendo's online efforts are not new. Beyond that when looking at the world at large, something it usually wise to consider from time to time, online games on consoles goes back many years; even sticking with mainline stuff the genesis/megadrive had stuff in Japan, big franchises like Phantasy Star no less, and online play on PCs has massive history, online emulation of old console games (see Kaillera) happened for years and
A best Nintendo have been caught with the pants down and have been awkwardly fumbling ever since while the others make a pale imitation of greatness. At worst Nintendo were wilfully negligent.
Also proper world class online infrastructure at the levels Nintendo wants takes a tad more than "a lil more".