Why do people do this? Waste!

I offered a guy 10 grand in cash, I had it in my hand, for a 1970 440 six pack cuda, ten years ago and he said he would let it rot or give it to his nephew before he would sell. It had been sitting outside his old beat up garage since 1986. Its sublime with a shaker hood and a pistol grip. I went by there a few months ago and it still there but starting to look really bad, breaks my fing heart.