I doubt it's really baking itself; most devices have a lower temperature target set in the software/firmware so that the user doesn't burn their lap, but the default thermal management behavior is done completely on-die.
I always wonder whether the heat calculations are correct. For example, if you compute the equilibrium temperature in a room on a table, then you get a cooler temp than when sitting on a lap that is 98.6 F. If the temperature sensor is near the CPU (i.e. one boundary of the heat equation solution), then it might not see more than a degree or two difference in very different external environments.
I doubt it's really baking itself; most devices have a lower temperature target set in the software/firmware so that the user doesn't burn their lap, but the default thermal management behavior is done completely on-die.