Why has amplifier power become a big issue

I guess that for my room in my NYC apartment listening to the music I listen to (small jazz quartet/quintet) the 50 watt amp does it for me. I have other amps up to 200 watts per channel from other manufacturers that I can use if the mood strikes. I just wanted to ask to see what has changed in peoples perception of sound that keeps the power output on some amps going up. Vandersteens aren't the most efficient speakers out but they don't present to many problems for most amps. I know listening to volumes greater than 85 db for long periods of time isn't great for your hearing. I listen at volumes that require a couple of watts and the transients require maybe 20 watts for short bursts and that can be covered by my 50 watt amp, no?

Nothings has really changed.  Loudspeakers with a sensitivity  in the mid-80s will sound perfectly fine with 30-50wpc.  Of course these same loudspeakers will sound better with 150-200wpc when played at louder volume levels.  However, if your typical listen level is 75-85dB, then 30-50wpc is sufficient for most types of music.

It's been my experience that if high volumes levels are required that high sensitivity loudspeakers is a better route than high wattage amps.

Modern Class D amps are very efficient and solve the problem nicely.    Without them I'd be more prone to go tube amp (not efficient generally) and high efficiency speakers to pick up the slack there. 

Power specification is very vague.  Average music power is only a few percent of the peak power.  Headroom of the amplifier is very important but most of the time not even specified.  

I also enjoy  my class D amp, especially at lower volume.  It does not loose composure, provides perfect imaging and strong bass.  It is closer to tube amp, in sound, than any SS amp I had.  In addition many amps, including my class D amp, have soft clipping, protecting tweeter from excessive amount of HF harmonics.

I think class D amps are modern marvel, but they don't truly solve the problem.  Feeding mega-watts into a moving coil loudspeaker will result in thermal compression unless you over build the loudspeaker which makes it too massive to properly respond to transients.

A 93dB sensitive loudspeaker with a 50 wpc amplifier will have an equivalent max volume as a 85dB sensitive loudspeaker and a 300 watt amplifier.  I just think the former is a more elegant solution.