The amount of DECs that Jet2 are recruiting it shows they have no interest in promoting from within or they make the process too hard and have a high failure rate.
Do you actually work at Jet2? There are unprecedented numbers of upgrades happening at the moment, and there are more to come. The external DEC recruitment has always been a necessary rather than a preference. Some haven't made it through the upgrade process, the process has developed and the success rate has increased, however not everybody will make the grade, surely that is a good thing, if you aren't quite ready then you aren't quite ready, a Command is not a right. Standards have to be met and maintained.
You might well get your Command slightly more quickly at Ryanair, but you'll have to disappear to somewhere you don't really want to be for it, and from what I can remember of a post a while ago, you'll have to pay for the privilege of you're Command upgrade course.
Jet2 isn't perfect, but I still believe that, all things considered, I am better off at Jet2 than Ryanair