Absolutely.
Yes, as Millercarbon say, there are some space and cooling limitations to an active speaker, but with money, many can be overcome. So in theory, not impossible at all. And as also noted, there are significant opportunities when one can fully characterize both the load and the transfer function of the speaker - and in effect compensate for those irregularities. In a cheap, mass-fi world this is precisely what Bose does and what every expensive in-car manufacturer does. Why? because cars are insanely irregular acoustic environments and benefit dis proportionally. While i have not heard the latest, i think the flagship Meridian system is a case for the active approach.
Now most active speakers are far more compromised, but we must still compare an active speaker at $2k, with, say a passive speaker at $1k and a relatively modest -- and imperfect -- power amp at another $1k. Better? dunno - let your ears judge. A simpler package? You bet. And for some that will win right there.
Control theory is a powerful concept. It is the basis of most rocket science and robotics and self-compensating weapons. Active speakers are how one implements control theory in the music world.
Whether the practitioners get it right is another question.
G
