There is economic theory that can explain all of the dynamics at play. None of this is "new" but people just don't like reality sometimes.
yes, and I know this theory (or a combination of):
1) Monopolistic competition: given that each product is unique, some people are willing to pay more for a particulate product even when similar and objectively higher quality products are available on the market for a lower price.
2) Market imperfection - transaction/search costs: once a person find something that is OK in quality, he stops searching
3) Asymmetric information and signalling (combined with mental transferring a paradigm from one platform to another): in competitive markets higher price is usually a signal of higher quality. If one use this signalling argument to apply to a monopolistic competition market of SPs, he would incorrectly believe that independent SPs are better than agency girls simply because independents are charging higher price.
4) "fair trade" movement: like with coffee, people are willing to pay more for a coffee if they know that plantation workers got pay higher wages ("fair trade"). Similarly, people who believe that poor SPs, who have to do such a disgusting job of slipping with different man, must be compensated "fairly" for their effort (i.e., more than the market price)