You have it correct. He was showing you the woman, just like showing you a Rolex. A form of conspicuous consumption. Plus in this type of hobby it's hard to brag to many people about your "conquests" thus he showed it to you.
Attractive and more educated woman in this hobby usually command higher prices. If you're paying to sleep with a Harvard Law grad you're going to be spending a heck of a lot more than you spend for your average provider. It is not to say you'll get better service, but it's more culturally prestigious.
Also providers that can market themselves well as upscale can also try to command higher prices. Doesn't always work.
Woman are used to be something to show off, which is why there is a such thing as trophy wives.Yet again it's a culture thing.
The guy was simply saying "Yeah this is the class I'm in because these are the woman I usually sleep with"
Watch groups of friends hang out, you'll notice that usually they are all of the relative same attractive level. There are outliers of course. When people get older it is more the same socioeconomic level. It is what it is.
