alt Hacker NewsModern solar panels last around 30 years, so I wouldn't exactly call it "short-lived".
Economically, I'm sure the locations chosen were optimal. You'd imagine that actual mountainous wilderness would be a much more expensive terrain to blanket with solar panels, compared to flat areas. If there were other choices, economically they'd better options.
Given the vast amount of flat, well-lit terrain within the borders of China, it should be clear that the pictured projects (and the other "blanket a mountain in solar panels" projects that are easily discoverable) are not about the economics of power generation.