Lot of stations that don't show ... are they doing better "in-demo" or do they have a different business model that sustains the thought of keeping it a "going concern". Take Hubbard's 1150, for example...is revenue from air time all that they need and it is not dependent at all on showing up in ratings? Same with 1540 and other ethnic-specialty programming (or others like 1050, 1460) -- they doing okay keeping the lights (and transmitter) powered up with donations, community advertising, or whatever?
The cynical side of me says many of these have outlived their usefulness -- but if they still serve a community under their own business model ... so be it.