Rant - recieving parts

Why is it that whenever I buy a piece of trim, or emblems, or anything for that matter, I never recieve the mounting hardware as well? When I buy a certain item, I need it to come with everything, including the hard to find clips, screws, bolts, nuts, etc. I understand if maybe the screws are rusted or the part has been laying around for a while and the nuts are now gone, but c'mon, that can't be the case for every part I buy. Is it that people are holding onto this hardware for themselves? I now have a bunch of parts laying around because I don't have the hardware to mount it.