As an economist I'd argue it's a mix of scarcity and good marketing. Actually it was first planted as a more resistent variety to leaf rust on one farm in Panama (Esmeralda). They took it from Ethiopia, so it must grow under different conditions (guessing it has to be above 1500m like all Arabica coffees). This actually implies that it might even be less complicated to grow than some other Arabica varieties, leading to the conclusion that it cannot be due to the difficulty of growing it.
The quality is definitely very good, since it was winning prices as "the best of Panama" since 2004. It also scores consistently above 90 (exceptional quality) in the Specialty Coffee Association of America (SCAA) score. However there are other coffees that score as high or higher and cost only half and less of the price. Thus I'd guess it's mainly a combination of little supply (because for a long time it was only grown on one farm) and telling a nice story about it, that made roasters want it. The taste certainly helps, but can in my opinion not totally explain the price differences.
I'd say this holds true in general. Supply and Demand plus marketing your product as something special determines the price. It's a form of market power to differentiate your product from similar products (substitutes), to make it stand out. Just look at Kopi Luwak espresso. It is arguably the most expensive espresso just because it has passed through civets digestive tracts and is then handpicked out of the fecal matter. The production process is quite demanding, which limits production quantity and gives it a good 'origin story'. Never mind that it tastes like what it actually is.
Highest Rated Coffee (Coffee Review)
Geisha ( Hacienda La Esmeralda)