Late to the party but here's my take...

PAX: I suspect the issue with PAX preferring jets is mostly OBE (Overcome By Events)...that was relevant when gas was cheap but the evidence shows when push comes to shove most PAX will sort fares by price on Orbitz and buy the cheapest.

Big Turboprops: Should have a future, as long as they're not too fast. Like somebody else said: fast = big engines = more fuel burn = little cost advantage over RJs. Again PAX sort ticket options by price, not time spent in cruise.

Big TP's MUST have significantly lower fuel burn to compete with RJ's...they are more complicated, so they're not cheaper to buy or maintain.

Small TP airliners: Nobody wants to make new ones. Why? Because they need all the same expensive technology that other airliners have but with fewer seats they have a smaller potential ROI. If it's a lucrative market, airlines will just fly larger TPs or RJs half empty and still make money. If it's not a lucrative market they'll be driving to the nearest big city (or flying on caravans courtesy of EAS).