Why has amplifier power become a big issue


Back in the day I drove my Advent speakers that were very inefficient with 30 watts per channel. Today I run Vandersteen 2 ce speakers which are more efficient then the old Advents with 50 watts per channel and way more current. By most this is underpowering the Vandersteens, what has changed?
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Looking at the measurements here:

http://www.stereophile.com/content/vandersteen-2ce-signature-ii-loudspeaker-measurements

I'd say that's a pretty amplifier friendly speaker. The impedance dropping into the deep bass may be helped by a stiff amp though nothing outrageous. I would imagine a number of good small amps would drive it very well such as the Parasound Halo A23. 125W/Ch and good with 4 Ohms.

Based on the measurements, this speaker by the way seems to have an impedance compensation network specifically to make it easy to drive even with modest powered tube amps.

Some of the sounds speakers make, such as a sharp whack on a drum, a firm pluck of a bass string, a loud voice or voices, the plink of a piano key (transients), can require lots of watts for a very short period to reproduce the leading edge of those sounds optimally.

A 50 watt amp may or may not be able to deliver the necessary power to reproduce them optimally, depending on the speaker and your listening tastes. If you are happy with the sound you’re getting from your system, you don’t need a more powerful amp.

Also there are a lot of speakers that are power hogs that don’t sound good unless driven by a powerful amp.

Im using PASS 350.8 on Magico Q3 having all this power gives me better bass definition and weight. It also lets my amp run in class a much more giving an overall better sound.
I agree that some (most?) of the complex multiway speakers can sound more authoritative on transients with more watts. But for the same dollars, a lower power amp may sound more musical.  There are now amps that combine musicality with big watts, but it can be an expensive proposition.