I've never seen anyone shamed. Just because few folks take them up on their offers doesn't mean they're being shamed. And, as I said, there are many longstanding for-pay fiction sites that seem to be doing quite well. All of these writers began as fanfiction writers, so I don't follow the argument.

A large majority of fan artists wouldn't get commission requests if they offered either. You have to be GOOD to make money off your creations.