In a perfect world every airline would make good training a company priority and spend what ever it takes to do it right. In the real world training is a cost centre and cost need to "managed" (ie reduced). In the real world, especially for Part 121 Regionals, the bare minimum of tick the box training is the norm. Meet the absolute minimum standard and you are good to go. I think the only reason that airlines could get away with this was because up until recently, new hires almost invariably appeared with solid Part 135 or corporate experience including ME and IFR time.
Sadly the massive diminution of terms and conditions has driven the experience level of new hires down. Expecting the airlines to spend the money to properly train a 250 hr new hire is IMO a fantasy. Demanding an ATR is not the ideal solution but it is not subject to interpretation. It will make sure that new hires bring some experience to the job instead of the guarantee that a 250 hour new hire will have none and be totally dependent on the quality and effectiveness of the airline training system.