As some users had already mentioned, it's not solely about experience on xyz aircraft(s). It's about
- psychology
- personal factors (stress management, mental strength etc.)
- Basic flying skills
- CRM
- airline training
In Europe many airlines do their own screening with 18 yr candidates direct from high school, train them by their policies and have a success rate of over 90%. Nevertheless, there are also some ready entries, but they also have to pass the screening.
This works fine with KLM, LH (Group), IB e.g.