> Oh, I completely agree—but they're so frequently used as a gotcha for why the rise of solar is just trading one "foreign master" for another. "Oh no, solar panels rely on rare earth minerals, so that means you have to kowtow to China!!!"

> And it's true that there is some in them, so it's good to have at least a long-term answer for how we deal with them.

It's the old saying about a man and fish and giving vs. teaching.

Solar panels bought now, at least the quality glass-glass kind, doesn't really go bad in a way that makes them depreciate at-all-quickly. If in locations that are not themselves at a premium, so lower yield only matters if maintenance overhead per yield becomes so bad it's cheaper to replace& upgrade, they can be expected to stay there for 30~50 years depending on how fast they'll mechanically fall apart after their warranty expires (which is expected to be the duration until which most stay alive). I'd guess something like an agricultural east/west fence install would stay more towards 50y and get individual modules replaced when they break, as they're easy to get to unlike roof/wall installs and the like where they're hard to get to and given they are very low complexity in mounting system ("fence panel") there's little engineering complexity in retrofitting a plain new future panel of the same physical size and sufficiently similar voltage/current.