From what I understand, it's not as simple as that. From what I have been told, PS3 is a real pain to port to. My guess as to why it's still supported is that a) developers are assuming that PS4 will be coming out eventually and that

PS4 owners will still be playing some PS3 games. Sorry, but owning a PS3, to me, is kind of like living in NY and being a Mets fan. O.o Seriously, though, I've knowna few people involved in PS3 non-native dev and they've all said the same thing, porting is a major PITA, and it's the fault of PS3. Kind of like web/java based dev with Safari in mind, I guess, where we are, apparently, in the year 112 according to Safari's interpreter (IE returns 2012, Firefox returns 112). I'm not privy to the exact reasons, but my guess is some stuff that's bass ackwards like that.
Well i'm not in the industry anymore( and was a hardware guy for PCs when i was ), but from all i've read and heard from those i still know in the business, the issue is most likely memory. I mean comparing PS3 and xbox 360 (its closest competion atm), spec-wise they are not that dissimilar. Shoot, the processor the 360 uses is, if i'm not mistaken, is a proprietary offshoot of the same tech that is in the PS3s CELL. The main difference between the two outside of flavor stuff(display mode, sound, media compatibility, etc.) seems to be memory. Or rather memory setup.
Both systems have 512 total. 360's is all of one type if i remember, while PS3s is split 50/50 for video and other functions. To me at least, its baffling that Bethesda hasn't learned(or at least asked others for) reliable tricks to overcome memory issues at this stage of the PS3s lifespan. Or if they can't get past memory hurdles, why not just kick more of the load onto the CELL? But i digress.
My ultimate point though is, after 6 yrs of possible exposure to the PS3 and undoubtedly having access to developer kits and technical specs we the public don't, the whole "PS3 hard!!

" excuse is a WOEFULLY inadequate as a reason for anything. With anything of course encompassing the whole gamut of issues involved in this current progression of events.
As to owning a PS3, i like playing games. Playing them, not prepping to play them. When i was younger and heavy in the PC scene i went to shows, conventions, and was constantly upgrading my various PCs. Quite frankly i just got tired of it. I want to play a game now, i pop it into my console and go to town. No niggling thoughts on if i need a new video card driver or have to tweak the registry for the 18 millionth time or any of the hundred other things that i came to loathe about PC gaming.
True, any console is going to be obsoleted. And they are are almost always going to be 'inferior' to a top of the line PC. But there is something to be said about simplicity. PC guys(myself included in this generalization) can sometimes focus so much on having the the most awesome rig possible, they forget about the simple joy of just playing a game.