You can't dominate a market without 3rd parties, as we know, but the fact is, Sony isn't realizing how difficult it is for 3rd parties to be profitable.
As I've said before, in my really large post "Biggest Blunder of Next Gen", the hardware companies have a responsibility to provide the game developers a good mode of transportation (the hardware), to help them create their work of art. However, because of the insane costs of major-next gen games, costs are very high, with very low returns (as compared to last gen).
10 years ago, there only needed to be a few incentives, as games sold well in 1995. The main issue was the ease of development, and if the 1st party was friendly, and wanted to take steps to make good hardware for the developers, as it meant lower development costs, and more freedom. Because of the easy-cheesy PS1's archatecture, cheap price (for the mass market), and CD drive, devs could make a good 3d game cheaper than on the Saturn, and easier since they didn't have to worry about frame buffers, or more expensive cartridges like the N64.
So what happened? They jumped the N-boat and S-boat (its not like Sega didn't get butchered that gen either), and went with a platform that made games cheap, and really didn't hamper devs from working on other systems.
Now, the issue is that even if those things are there (friendlyness, ease of archatecture, ect), the fact is, it still costs more because of archatecture. At this point, devs need more financial incentives. Because of this, MS realizes what Sony doesn't. You either pay the loss of cash the devs have to make for a really big game, or it goes multi-port, and you lose cash, as the licensing fees are going to the other hardware makers.
Ultimately, I feel that in order for 3rd party exclusives to ever become a reality again, the hardware makers need to either subsidize them (like what MS has), create new ones (like Nintendo/Sony have), or offer them a better, more profitable platform to work from. Nintendo is doing it via lower hardware specs, and MS/Sony are kind of left in the middle of nothing.
However, MS/Sony could easily do a few things:
1. Produce/License more middleware applications (like both MS/Sony are doing), to allow devs to have a better universal library of information to build a game quicker (and cost less).
2. Give devs a better platform to release games on. MS has done this via the very, very, very lucrative DLC platform. Did Shivering Isles cost 1/2 of Oblivion's budget to make? No, it might of cost 5% of that. Despite that, it still sold for $30 a pop. Because of this, developers get a better platform in the way of very profitable expansion packs. This is similar to the fast food chain's way of profits, make very little off the initial sale of the main product (a hamburger), but make a 1000% markup on the Soda and french fries.
3. Give them a better platform to make money for more prolonged periods of time via more and better distribution methods.. I thought about this: how do movie studios make so many big budget movies ($100m+) so regularly? It's a fact that a studio has to invest hundreds of millions of dollars into a movie that might bomb. However, the 2nd tier of profits are in DVDs. DVDs like Finding Nemo easily sell 20m copies over thier lifetime, and at an average profit of $5/disk, that's alot of extra, profitable money. Not only this, the distribution methods for the DVDs allows for more time on the market. A movie might stay in theaters for a few weeks, but a DVD lasts a lifetime. Terminator 2 made $200m at the box office, but cost alot. Why was it so succuessful? You can walk into Wal-Mart and buy a T2 DVD for a few bucks.
Gaming only recently has developed a method of keeping a game out that long. I feel that #3 is the most under-developed method of this via downloadable classics, and older games. Only until recently could you get a copy of Super Mario Brothers on SNES via illegal ROMs. But now you can buy them on VC, and Nintendo is making an absolute killing. Why is this such a lucrative, good method of getting sales? It's a permanant way to retail and sell your product. Mario is never, ever going off VC. And because of that, it'll keep selling until the Mario name is dead.
IMO, I see a world in the future where I can download Halo 1 or Halo 2 off XBLM, or find KOTOR on the setup. This allows soooooo much incentive, as a developer can keep getting tens of thousands of dollars off an old game, by selling it for $5 to interested parties that never got the chance to play the old game. The most critical part is, again, it's PERMANANT.
Until those 3 things happen, the only way to get an exclusive is to pay for it. MS is smart because they care about exclusive games, as I would tend to think exclusive games are better games, as the devs are able to utilize the system (whatever system), better.