My N. burbidgeae has been sitting for about 5 months now, and i'm starting to see a little pitcher growth, not much.
My N. maxima has been sitting for 3 months, and i've got about the same growth.
This is from the time i bought them mind you.
So i guess it also depends on the plant.
The same thing happened with my two ventratas. One pitchered the next month, the other took 4 months to pitcher.