Old china, RJ's were a bad idea until they took off 25 years ago. The A380 was a dead end for many, until recently. The Cseries under the 737/A320, don't go there.. The 100 seat E190; haven't you seen what happended to the F100 & BAE146? Just no market.
Hopping around with 40t birds is OK when fuel is cheap. It aint.