Eventually it might get to the point where every new TV being produced is also 3D capable but when you consider how long the adoption of HD took before it got mainstream, I really can't see this taking off any faster. I bought my first HDTV back in 2002 and there was one channel available in my area.
3DTV requires consumers to learn not only about HD, but glasses, Blu-ray, HDMI compatibility, new channels, which providers, which programming etc.
HD was a relatively easy concept to grasp by comparison and people still didn't get it.
It also requires more bandwidth from providers. Something the majority of which cannot deliver for HD content.
People hate the glasses so much a new tech is bound to come along before 3DTV in it's current form becomes mainstream. In which case why jump in now unless you just want to spend a lot of money for the novelty value?