Demand is ALWAYS low when trying to produce an industry driver, its the way it works. See BluRay, Motion control, DVD, 3D graphics cards, Natal etc.
The way it works is simple - predict where the industry is likely to go, implement prototype units, showcase the application of that product and hope like hell you've read the industry right and your entry price is low enough, or you are happy with slow takeup early.
In this case, from the demos that Sony showed of GT and Wipeout running in 3D, it was absolutely stunning. If this is what they are looking toward...hell mother f*cking yes please.
Sony are not the only one's hedging their bets on 3D either. All the current TV manufacturers think the same as everyone of them has units coming. There are BluRay 3D players coming. Sony implementing it in the PS3 means that it is striving toward mainstream launch for PS4.
But all I know if they release Killzone 3 in 3D with nunchuck and wand, I'm buying a 3D set and not turning the thing off ever.