(30-11-2018, 06:27 AM)jkl Wrote: The main reason I could imagine is that a graphical interface basically steals CPU cycles on common operating systems, making the "supercomputer" less "super". But this could mostly be solved by writing the OS around a GUI. I doubt that it is impossible to write a native low-level GUI for a processor that wouldn't impose a barely noticeable load on it.

This is one reason, the others are plenty. The two other most common ones are:
* Adding softwares also add the scope of possible security issues
* Not all servers come with a screen and doing graphics over the network is expensive

(30-11-2018, 06:27 AM)jkl Wrote: Which has not been solved once and for all just yet. :-p

Always an interesting conversation to have.