I think my 150lb speakers and umpteen voice coils are not heating up with my 10 wpc amp running at 1/3 power. Efficient speakers and low power amps is my preference. That said, a well designed speaker that runs on much higher current should have plenty of current capability. For example. Crossovers usually use 15watt resistors for low current so they won’t heat up and change value.
Thermal Distortion your loudspeaker most likely suffers from it. But do you care?
Thermal Distortion is much more serious than just a maximum power handling limitation or side effect.TD is overlooked by most manufacturers as there is no easy (low cost) solution and TD is audible and measurable most of the time at most power levels. TD is caused by the conductive metal (aluminum, copper, or silver) voice coil getting hotter when you pass electrical energy through it. The more power you pass through it the hotter the metal gets. The hotter the metal gets the more the electrical resistance increase. The efficiency goes down and you need to ram in more and more power for smaller and smaller increases in SPL. It can be the reason you get fatigued while listening. If you are running massive power you are creating more TD in your transducers. But do you care? And is it a reason some prefer horn-loaded designs or SET-powered systems since they have the least problems with TD?