3D may be invevitable and unwise to resist, but that doesn't mean film makers should embrace it now. Let's face it, it took 30 years for the movies to really transition from B&W to color. Many great B&W movies were made after the color debut. For decades it made economic sense to stick with B&W.
Likewise, until 3D cameras become cheap and convinient, it may be better for most filmmakers to skip it. In the long run 3D may win. But, if you want to make a film, it's better to make it with the tools at hand, then go the extra mile and expense to make it in 3D.
How many movies really would benifit from 3D? Sure, the summer blockbusters will. And probably animated kids fare. How about a Romantic Comedy? A drama?
I predict it will be a long time before a 3D film wins Oscar for best pic.