What about anything you said is a "major challenge"? They lose efficiency, yes everyone knows this and can plan ahead. They can fail like anything else. But

What about anything you said is a "major challenge"? They lose efficiency, yes everyone knows this and can plan ahead. They can fail like anything else. But they can be re-used and replaced. If you need to replace your roof, you just remove them and re-install on the new roof. There's no magic to installing them, it's quite simple if you have any handyness. If not, just hire someone like anything else.