Hi Bob,
This is one time I doubt anyone can blame Glass (I know you were kidding).
My speculation and a few bucks will buy you a Starbucks, but here goes my list of possibilities:
1 - FAA certification - several months ago full certification was delayed due to "minor problems" (Embraer's words). According to Aviation Week, it had to do with software in the flight management computers. Seems to me that a "minor problem" could possibly have been cleared up by now, so maybe it is more serious.
2 - Money - not the financing, we'll know that's gone if we see that our credit rating is downgraded again. I mean the money for start-up. With the ATSB "liquidity" requirement hanging over our heads, every dollar not spent is a dollar that doesn't have to be offset. I find it interesting that with the provisional certification of the -170 in place, there have been no required proving runs made (that I've heard of). But flying empty airplanes around costs money, doesn't it?
Given a choice, I'd bet on #2, but wouldn't discount either.
Jim