Sorry Pug, accepted that some of those types went in once before, but rules have changed since then, more constrainining, more limiting. EASA progressively toughening up on minima etc.
All those smaller aircraft types are that much older too, costing more to operate, less spares etc. whilst economic environment is horrible, APD charges ever higher (which hurts the smaller aircraft more), ETS introduced - everything against the small regonal operator with small regional airliners.
Just too tough at that level to make a living, or for that matter simply survive.