Not sure why decoupling would matter for a SS amp but have not really thought about it. However, I prefer my amps off the floor mainly to reduce the chance of dust bunnies etc. getting into the cooling system. I would never set an amp (or any electronics) directly on carpet due to dirt, dust and fibers.
my floor is hardwood where my amp(s) are. and my darTZeel amps are sealed (and they are Swiss), so dust bunnies are not a problem. and none of my gear sits on carpet or sits directly on the floor.
p.s. High-resolution flight electronics are way more resolving than audio systems and include a high degree pf specialized mechanical isolation, SS or not...
or even just consider the modern Automobile. everything is ultra-engineered to be attached in an optimal way. one reason it costs 2-4 Billion dollars for a model change over. these are not trivial matters.
p.p.s. How did this thread end up under "Turntables"?
above my pay grade.