I think this applies to people in general. I'm in the banking/lending business, and it is interesting to correlate your comments with the clients we provide financing for. The most affluent, and especially the long term well to do, are generally the easy to deal with, while those who've recently found success or even worse, those who've recently come into a lot of money that wasn't "earned", can be some of the most difficult to deal with. At the other end of the spectrum, the "average Joe's" and those just getting by are mostly a great pleasure to serve, as they are very straighforward and appreciative of good service.
I think "Big Leagueing" occurs in many walks of life, not just professional sports.