It could. The available fossil sensible heat energy is something like hundreds of millions of years of sunlight. Right now geothermal is uneconomic except in special situations, and human world marketed energy consumption is four orders of magnitude smaller than insolation, so it’s not yet a practical concern.
It turns out to be millions of years of sunlight, not hundreds of millions.
You have: earthmass 2000 K 1J/g/K
You want: J
* 1.1944337e+31
/ 8.3721685e-32
You have: earthmass 2000 K 1J/g/K/(circlearea (earthradius) 1000 W/m2)
You want: years
* 2968252.9
/ 3.3689851e-07
