Have you done away with your Class A Amp due to Heat concerns? No. Because mine don't generate heat.
Will you be moving away from Class A Amp due to Heat concerns? No. See above.
Will you never buy a Class A Amp due to Heat concerns? No. Mostly because I'm not going to buy another amp.
Let me state at the outset that I own SS amps. Monoblocs. Actually, SS exclusively along the entire signal path.
A few extraneous thought arose as I read through the thread. I keep my house at 63 - 64 degrees in winter. The room where my amps are is slightly colder because it's over the garage and the thermostat is down the hall.
The majority of responses focused on tube Class A. I'm not going to defend SS Class A or denigrate tube Class A. You listen to what you like and what pleases you. Many years ago, before I bought my system, I read a lot of arguments about tube versus solid state. In that reading I found a gem of a statement by one of the better well-known designers. I think it was Carver, but I could be way off with that. The statement was, essentially, that solid state amps could be biased to sound like anything... tube included. The bottom line is decide what you like to listen to, then buy the best you can afford. I found what I liked and bought that. I guess they were biased correctly for me.
If you really want to get into the climate change concerns, answer these questions for yourself. What car do you drive? The amp you're running is minuscule compared to a car. For myself, I got rid of my ICE vehicle and will drive 100% EV as soon as it arrives.
Whatever you drive; how many times do you walk instead of drive? I walk a lot (and did so before I got rid of the ICE.) Maybe I'm lucky in that I live in a neighborhood where walking is feasible. It only takes me 30 minutes to walk to the supermarket or hardware store, etc.
What temperature do you keep your house at? As stated, I keep it 63 - 64 in winter. 73 - 74 in summer. I live in the northeast. It gets both cold and hot and humid.
To brian61. You really should have differentiated your question between SS and tube amps.
Happy listening.