Nah I just don't see it happening, and I don't want it to happen. PD has it's own, sometimes headstrong way of doing things, but I feel it adds it own character to the game. Something which most games lack.
Many issues with outsourcing. Increased cost in addition to 140 employees, quality
may not be up to PD's high standards (can be fixed but takes additional time), keeping their game code a trade secret, pride in doing everything in house, etc. etc.
Now if PD do hire 160 more employees to match Turn 10, do you think that increased cost will be offset by increased revenue? I'm betting your ass not. Most of the stuff people complain about here doesn't matter to the casual masses, who make up most of the sales. Remember PD is a business, and if PD goes out of business there's going to be no GT, which will make me very sad.
I also have a strong suspicion that Microsoft is subsidizing Turn 10 significantly more than Sony. Sales numbers are nowhere close to GT (DLC sales are definitely more, but I'm guessing a drop in the ocean), and if I were running a company I would take 140 employees with a truckload of sales over Turn 10's situation any day. The fact is Microsoft is making a ton of $$$$$, whereas Sony as a whole company isn't doing so well (though I think the entertainment division is doing OK). So they can afford to keep supporting Turn 10 through periods of losses a lot more than Sony can support PD.
Kaz has said sounds will be fixed in a later update. I prefer 400 premiums and 800 standards to 200-300 premiums (not sure on Forza's car numbers). Prefer more tracks. Like the fact that PD continue to support and develop the game further for free. I like the fact that PD seems to be on amazing terms with car manufacturers (which bodes well for GT 7,8,9....). And the new physics

.