Judging by the price tag of 9.1 Ksh/kWh listed on https://en.wikipedia.org/wiki/Energy_in_Kenya (and looking up historical exchange rates because of the date of the link and their persistent inflation), that's about 0.085-0.090 USD/kWh.
iirc it works well in Kenya because the thermal gradient is really steep and the heat is right near the surface. I don't think that's common around the world. Local expenses (labor, etc...) are also cheaper than in many parts of the world.
Geothermal is however one of the electricity sources with the fewest negative externalities so definitely should be pursued where possible.
Touring the geothermal at Hell's Gate Park in Kenya is wild. If you've seen The Lion King, it's the inspiration for "the shadowy place over there" where the hyenas live.
Extract enough heat from Earth and Earth loses its magnetic field and then its atmosphere and oceans (from the effects of the solar wind) which sounds like a negative externality to me.
While it's true we would die first, I bet we'd transition to other power sources even earlier. If we ever get fusion working reliably, that will probably be more convenient than geothermal, and at that point the geothermal plants will start slowly going defunct with no replacements.
If you haven't done a calculation incorporating an estimate of the heat content of the Earth's interior, then you cannot know whether humanity will be dead by then.
Geothermal is however one of the electricity sources with the fewest negative externalities so definitely should be pursued where possible.