Pugilistic Animus
it's not about the absolute temperatures it's about how fast the heat can be dissipated transfered to cooling medium such as fuel; do a PPRuNe search for 'ram rise formula'...
And I assume some energy is re-radiated back into the air? I do distinctly remember reading that if you flew at a given mach number at two different altitudes you'd get different skin temperatures which I was under the impression at the time had to do with the thinner air able to impart less heat to the plane, and the airplane's structure naturally able to radiate away a certain amount of heat.