Yes I absolutely agree that it would be far more economical for Ryanair to employ the new cadet and use him/her to the max hours as opposed to a 2nd or 3rd year FO but as you infer it's not a simple explanation. I will add that for rostering to achieve a discrimination based on one's experience at Ryanair, there would have to be blatant meddling of the rostering system which for a company this size seems a bit unrealistic. Also how such rules/logic could be built into a complicated, automated rostering system I can't imagine. (But then and again we are talking about Ryanair!!!)
Come on guys keep the facts coming.