Transistors transistors transistors. Need more transistors.
At least with tubes you could see it and swap out. With transistors who the hell knows what the heck it is. So the manuf company buy some transistors from China or some far off place and they stick it in the box and connect wires to it. Does anybody with a solid state amplifier know anything about the transistors being used. Is it communicated. Nooooooooo, it's never or poorly communicated.
At least when you buy food you know the ingredients.