Here is a quote from a certain famous book "Thou Shalt Not Covet Thy Neighbors Goods". Good words to live by.
Where I live, I have seen numerous similar situations, and have been sorry to see stuff rust away, or eventually be sold for scrap, but after all, it is their stuff, and their's to do with as they see fit.
Put yourself in the older person's shoes... they may have collected it with the intention of restoring it, and never had the time, or funds to do it, and as it is THEIR PERSONAL PROPERTY, sometimes it is just hard admit you will never be able to work with it due to age/health issues, or to face the fact you're getting up in age and facing death.
I had and Uncle who would fit the pattern of the scenario above. When he was in his mid to late 80's, he still wouldn't set foot in the local Senior Center. (They have noon meals and activities several days a week.) He always said he wasn't old enough. He had a tremendous amount of engines, etc., that he was going to restore "WHEN HE HAD TIME".
Time passed as it always does, and he eventually had a stroke, and lived out his last years in a rest home, finally passing away at age 93. As his POA, I had the task of selling off his stuff to pay the rest home. Due to huge medical bills I had for my kids, I was unable to buy any of it, and had to watch as it was hauled away.
I think there are 2 lessons to be learned here.
1.) If you are getting up in years, have a plan in place to dispose of you stuff, should the need arise, or get legal advise as to how to protect it for a family member who is interested in keeping it in the family.
2.) If you see a site with someone else's old stuff on it, try to accept IT IS NOT UP TO YOU TO DECIDE IT'S FUTURE, and try to put yourself in the owner's shoes, and realize there are probably some issues in his/her life that have led to the situation as it is. There is sure no harm in nicely approaching the owner about selling, but be considerate, and if they are unwilling to sell DO NOT BUG THEM!