The MPL is specific to an particular airline's training system and assumes the candidate will stay with that airline until he has enough hours for a full ATPL. Consequently, the MPL student will be recruited into a particular airline from the start of the course, or be sponsored. You will not find MPL holder finishing the course and then seeking work - unless the airline has gone bust in which case they will be screwed - as the MPL is specific to that airline. The non sponsored pilots will still have to continue down the traditional route.
My airline has only recruited cadets for the last three years and has now gone down the MPL route.