Meh, to most people old junk is old junk. I could show you my collection of old military rifles, and I doubt most could pick out which ones hold quite a bit of value and which were produced in quantities of tens of millions and once sold for $30 at local sporting goods stores on Black Friday. Sure, it is different when you are familiar with the brands and the market, but most simply aren't.

I agree with the comment above, the odds of something truly unique and deserving of being saved being found on the cheap or free that these artists work with is relatively low.

On a personal note, I don't see the appeal in any of those structures. They are rather ugly to me.