Yeah, one of the keys here is the excellent efficiency of those amp topologies! You just can't get that kind of efficiency from an old-school amp design. Of course, there are always advantages/disadvantages.
Since you are somewhat easily persuaded in this hobby
I'm gonna throw out another idea--You COULD build your next set of speakers with built-in amps
using some of those little boards, etc.
Then, you just need a signal and power for the speakers, and some type of volume control. You could even go the route of many computer speakers where 1 speaker has the amp, and the other one is just a pig-tail to the passive speaker.
Anyway, I have been considering a build like that for quite a while, just never got around to it.....yet