I wonder why they never filed a Form 15? That could have kept the party going for quite awhile longer.
I believe that initially they didn't realize that if they were delinquent, Rule 144 wouldn't be available to holders of restricted stock. Once they figured it out, they seem to have decided it was a good thing, because toxic lenders wouldn't convert and sell. They even said so in tweets and the like a few times.
Finally, though, KBM sued them. I haven't been following the case, but it seems to be proceeding slowly.
Filing a Form 15 would have been an automatic default event as far as KBM was concerned. And no doubt as far as any other toxic lenders they may still have are concerned. So I guess they decided to take their chance with the SEC.