Powered speakers can be a very nice approach, and they are probably more common today than they have been in the past. One challenge with powered speakers in home theater is the wiring, though. Fronts and center are relatively straightforward, but surrounds are downright tricky. You need 120V power nearby, and most folks would prefer it to be very close at hand to avoid running an exposed power cord all over the place. That probably means hiring an electrician to come install some extra outlets specifically for each speaker. You also need to have different wiring to the speaker, since speaker cable can't really be re-tasked as a pre-amp cable. Combine those two limitations with the fact that many home theaters are using receivers that lack pre-amp outputs, and you can see why the traditional approach of passive speakers and centralized amplification has remained so dominant.