The market for big turboprops hasn't been good for a long time, and really suffered in the RJ
craze. The ATP suffered against the Dash-8 and ATR-72 in that it didn't have a "smaller" child (I know, it was derived from the HS
748, but that's a significantly earlier "generation").
Performance was also, well, shall we be polite and say "stately?" I seem to recall an article in the last couple of years talking about a flight experience with Manx in the UK, and something telling was that, with a full load, they were only getting 500fpm climb at 8000 feet!
Operating turboprops at sub-14000' really hurts on fuel burn, in my experience (remember that half the atmosphere of the planet is below the 14,000' level).