Concorde, the great pipe dream "the BA retirement bulge" has in fact passed. With new changes to retirement ages coming in that will delay many guys leaving.
As was pointed out by Scroggs, the days of the fully sponsored cadet schemes appear to be gone for the forseeable future.
The "pay for rating" or "pay for your sponsorship" (ala CTC) are well established (unfortunately) and there would have to be a significant change in the number of people applying as well as a huge change in the attitude of the airline accountants.