Very interesting context here, thanks. Do you know of any write-ups that give a deeper picture of the progress of any of these (or other similar) projects? It seems that there are tough problems to be solved, but we're just seeing the marketing materials.
Another thing that should be considered: how do you keep the hole open while drilling? At extreme P and T, the hole will close in on the drillstring. Also, fluids turn very nasty in those conditions. You'll need some unobtanium and some of Superman's suit material.
