The NBL was screwed the day they signed the deal with Foxsports (that was after they still insisted on Ch10 showing live game IIRC).
Free to Air TV is wht got people interested in the NBL. I remember the days when you had Tigers vs. Magic on a Saturday Night with 10,000 at the Tennis Centre.
Those days are long gone now. I'd be looking to get games on SBS or ABC somehow, to try and pipe up some interest.
The move to Summer didn't help either. It was a good idea in theory (not competing in the same timeframe as AFL), but it backfired.
Soccer has shown that with the right administration, a sport can rebound.
The NBL probably needs a white knight right now to bail them out, and rebuild from scratch.