Yes, really. Compared to the widespread urban power needs for the United States there are damned few geothermal sites sited so they can be tied into the grid so as to get the power to them. (there "is" a limit to how far power can be transmitted, y'know).
In your original post you used the term "exceedingly rare" now you are comparing to the total energy needs of the USA. Let's look at the numbers and some facts:
Hawaii -- 30% of the power on the Big Island comes from Geothermal
Mammoth Navy I -- Produces enough electricity for 40,000 homes.
Mammoth/Coso Junction -- 273 MW capacity
Geysers -- Supplied enough for electricity 1.8 million people
Imperial Valley -- 327 MW total at 10 plants
Steamboat, Nevada -- 40 MW at Three Plants
Utah -- 23 MW
Yes compared to the entire USA those are small numbers, but exceedingly rare as originally stated is factually incorrect and misleading. Source: Geothermal Power Plants in the USA