The thing is about emulation is that once you write the software once, it's not hard to maintain going forward... Sony simply hasn't bothered to try until this generation (which, uncoincidentally, is the first time they've kept the same chip architecture two generations in a row, which makes BC stupid-easy and almost automatic). All past Sony BC involved them literally putting last generation's chipset somewhere in the newer gen machine, which is a pretty ugly solution (also expensive, which is why they stopped). From the beginning, Microsoft has always prioritized BC emulation (even when they changed architecture) and they deserve credit for doing so.
Anyway, my kids play Wii/U and Xbox 360 games all the time, particularly the motion/dance games, which means BC is pretty important to me (and I'd someday like to have fewer than *six* consoles plugged into my living room television). And frankly, it's a feature console makers should just offer to their loyal customers who may not want to be forced to maintain a working PS2 indefinitely if they ever want to play their PS2 games again.
I mean, there are literally open source, free emulators that do a pretty bang-up job up through really recent console generations running on $40 hardware. It's not a stretch to ask a multi-billion dollar conglomerate like Sony to add emulation to their $500 console.