I'm not sure what kind of answer you expect here. Your initial objection further up was:

> By the time the "free" electricity has paid for the installation, you'll need to replace it.

Since you won't need to replace it, I'd say that this whole thing couldn't work out better: the panels are literally just generating electricity for free! And that's not even taking into account that 30yo panels generate more than "only half the power" (the study I linked measured ~80%).

Imagine someone offered to give you their 30 year old panels and install them on your property for free. Unless every eligible surface is already taken up by more efficient solar panels, who would say no?