The disappearance of the traditional amplifier

What goes on in the pro marketplace does not necessarily translate to the consumer marketplace. I think that powered speakers have a chance in the consumer marketplace for the reasons Shadorne mentions and also for the fact that they are more neat and tidy for a home decor--no big boxes cluttering up the living room. B&O has been quite successful with this approach, for example, in the less-than-high end, and Meridian and ADC have had some excellent designs using this approach that I think most of us would consider high end. I doubt, though, that those of us in the lunatic fringe (and I include myself in that group) of perfectionist audio will completely embrace the technology, as it limits our choices (no tubes, as Rockadanny gently points out) and ability to "upgrade", and the perception (right or wrong, and Meridian's and ADC's powered speakers make a strong case that perhaps the perception is either wrong or overrated) that constraining an amplifier to such a small, vibration-prone space will be deleterious to the ultimate sound from the speaker.

These powered monitors got tubes in 'em? ;^}

As Chad mentions it is cheaper - it is easier to build a higher performance amp with limited bandwidth powering one driver than the same quality performance with very large bandwidth driving several drivers as well as a lossy passive crossover. Usually when something is both cheaper and better in performance it tends to win out in the market place. I suspect active speakers will win out eventually if not for performance but more likely because of lower cost for similar performance.

No its just cheaper and takes up less space.

Like the record I think it MAY in the main stream but not with die hard audio fans IMHO. I will always like the option using different amps, ect...