Suppose I were a rim manufacturer and I wanted to sell you one rim. First of all I'd have to do a bunch of marketing to get you to want my rim. I'd have to have some kind of consumer packaging and labeling, maybe some instructions. I'd have to pay a tech support staff to answer all of your questions. Also, I probably wouldn't want to sell to you directly, so there'd be some middle men all of whom would also want to make a profit on their part of the distribution process.

Now suppose that I wanted to sell 2,000 rims, all at one time, to somebody who builds a lot of wheels. Other than the actual cost to me of making the rims, everything else is cheaper, easier and faster for me to do. He's going to pay a lot less per rim than you are. Sorry.