LPFM can work in some instances. The curse of LPFM is it is for new entrants, mostly people who have never worked the business and don't understand you must have money to pay the bills (but we're non-profit was actually said to me...I said tell the electric company that and see what that gets you).
The best scenario is a small community where you are the local media.
A big city has a tough time because of lack of sense of community. Too many stations choose programming that rings true for .1 or .2 percent of radio listeners but only reach 20,000 people and therefore are doomed from day one.
I admit successful LPFMs are few.