It depends on how you measure "success". Even for commissioned sales peple, the $ they rake in may not be the indicator of how "good" they are. I have know MANY commissioned sales people who made good $, but got terrible client reviews, did little repeat business, burnt out quickly, and went on to a new line, only to do the same thing all over again.
I don't know any business where, if greed is your only motivator, you get high grades from your customers. In service businesses, the biggest key to repreat business is customer satisfaction. If you're in it for the long run, you have to be operatiing under some paradigm that gets the customer what they need ( in one way or another ).
OTOH, someone who trips over themselves to provide service above all else will shortchange themselves/their company. In this business the example would be the indy who is so affraid of being labelled a "clock watcher" that she gives 4 hour appointments and only asks for the 1 hour rate. Her customers will give her high marks for service, but she won't make the $ she should, and will attract, in general, a crowd of less than ideal clients.
One of the biggest disadvantages of being an independant is that it's very hard to "run your business like a business" and also get high marks for service. It is MUCH easier for a lady to focus on service, while someone else focuses on the business end. I would bet that if you were looking solely at the $ ( i.e. greed ), you would find that women who worked for agencies ( at the same "level", etc - whatever that means ), agency women make more than independants. To me, that's the largest single indicator that independants are not greedy. Either that or they are deluding themselves about the $. Of course, this isn't true for all independants. There are some which for on reason or another ( age, body type, etc. ) would not be hired by agencies even though they might be "good providers" ( what an ironic phraseology ! ), at least not at the $ level which they "exist" as independants. Generally, I would think, this includes ladies who offer a very high ;eve; of service, which would be hard for an agency to "sell", as different from their other "workers".
Anyway, as a result I think that the reasons for independants to be independant, should be other than "greed".