The MPL is an experiment, one that works with an airline that has high demand. I doubt that the model will be adopted as it has major down sides:
-It is not transferable from carrier to carrier, important retraining is necessary
-Brings issues when an airline decides not to hire a student pilot that is following a course after all
-Who bears the costs?Ok if the airlines pay for it but I don't think any pilot is crazy enough to enroll a program with such compromise
-The MPL is designed to put 200 hour pilots on an A320. Many carriers do not agree with that philosophy
-The validity of the license with foreign carriers (even within the EASA) will be questionable
-The MPL license can not replace the classic sytems. At best it can just be an additional option.
Ryanair could stick to this system if they think that they could make some money out of it.