I am not sure I follow your rationale.
If for example you leave flight school with a CPL/IR and get a job with say BA or BMI or Aer Lingus (only ones off the top off my head that offer free training) then you will go onto the year 1 F/O salary scale. You will get type rated and line trained at no cost to yourself. With each additional year of service you go up the pay scales.
AFAIK Easy only take low timer CPL/IR's from CTC so there is no real comparison in year 1. However, in the past you could conceivably join Easy from another airline as a inexperienced F/O with low hours on say a turbo prop or light jet. What most junior F/O's at Easy would say is that there is a big difference in salary between a direct entry F/O and a CTC cadet who as you point out is paying back a proportion of their training costs.
There have been calculations done and posted here on pprune in the past on the salary sacrifice and the "real" cost of going down the CTC route which you can read about. Suffice to say its not a sponsorship per se no matter how you dress it up.