I don't know what it is about induction that makes a rheostatic-like control unfeasible but the most I've seen is about 20 levels so you might be waiting a while.
Many more are a problem without a knob to speed through the steps.
There's no reason an induction hob can't be run with delta-sigma over it's normal low-resolution PWM to get accurate, high-resolution average power control.
1% power accuracy is easy, 0.1% is a few bucks more per "burner".
The problem I've seen with some induction hobs is that the low power settings are basically 1 second on / 5 seconds off, which is kinda annoying when the liquid goes between boiling violently / not boiling at all. Maybe thicker pots would help smoothing that out, though.
