If you don't work in TX/CO/LA, they are a huge money loser for groups. Multiple ones opening up here in FL, for some reason the competing hospitals like opening them up next to each other. They see low volume/acuity, low numbers. It's an easy place to work, but if you don't get the facility fee, they are big time money losers to staff w/ physicians. The one plus is that they're pretty easy to work at. I have no idea how CMG's are paying $220/hr to staff these things--they are definitely losing in millions at that rate.
In TX, the free-market won out, w/ multiple groups flooding the supply in big cities. With a flood in supply, the competition was too much, and late-comers/less financially secure groups lost out. Groups got greedy, and now the honey pot is gone. They can save the whole "underserved" area--I've never seen a FSED open up in an underserved area. They are always in the nice suburb, trying to steal marketshare of insured patients from the established hospital-based ED in the area.