The difference between the 360 and PS3 was there came a point where all MS became was a check writing and Halo factory. Paying for exclusive third-party titles and exclusive DLC became the norm. Sony chose to invest in new IP. When the smoke cleared Sony had a pretty good catalog of first party titles while MS was busy cranking out Halo/Forza/Fable sequels and writing checks. One strategy yielded The Last of Us, the other got us limited DLC for Call of Duty.
Sure, MS did rely on Halo, Forza, Fable and lets not forget Gears, but they also invest in plenty of Kinect games, including new IPs (as well as State of Decay for XBLA which was a great new series for them), I won't convince you the Kinect stuff is good games but investment is investment and considering how Kinect sold it would seem like it was a smart financial move while they were getting games ready for XB1.
MS got the 360 out first and it was easier to develop for and third parties wanted in which left Sony with a big hole in their line-up as big exclusive series like FF, DMC and GTA went day one on Xbox and they retained MGS4 but lost out on the collection and GZ/TPP going forwards.
MS probably did help sway them, its rumoured they paid mega bucks to get SE out of their FF13 exclusivity agreement I think? But it still happened and left quite a gap in Sony's line-up. Lets not forget the acquisitions Sony made just before or during their 3rd generation (which is what MS is at now) which I think was obviously done to bolster their WWS and help make up for the exclusives they lost:
Guerrilla Games/989 Studios - 2005
Zipper Interactive - 2006
Evolution Studios/BigBig - 2007
Sucker Punch - 2011
Media Molecule - 2010
Sony did have a big first party line-up anyway but those additions made a huge different to them Sony have invested in new IP with their first party line-up. Also consider 3 of the studios above (2 shut down) will release major titles in the first year of the PS4.
MS have been bolstering their first party studios recently, similar to how Sony did, only without as yet buying any "AAA capable" developers recently.
This goes back to the age old argument of games aren't built in a day. TLOU was a result of years of work on a new IP! But Ryse was in development for 7 years and came out 5 month after TLOU and doesn't count as MS investment in new IP with Crytek? What about Sunset Overdrive which is out this year? I don't know when MS signed the deal, but clearly they are investing in new IP. Quantum Break too was give the green light in 2012?
Also, Sony get exclusive third party content. One strategy got you TLOU and other new games, but the other one got more Halo and established IPs but new Kinect games.