I don't see the logic. If the training is expensive that is one reason why so few pilots can afford it and is one of the prime reasons for the shortage, surely? If it was cheaper there would be more pilots available because more people would be able to afford it.
In the US there is also the requirement for a pilot wishing to fly for an airline to have an ATP with 1500 hours and a very expensive period of time in a major simulator, which all adds a lot to the cost. A youngster in school looks at this and most often decides the cost and time are way not worth it given that she will be nearly as old as Dad when she gets her first real job. Especially if she also wants a four year degree which alone will cost more than the pilot training.
In the good old days one could aspire to an airline job, at least in the Regionals, with around 800 hours which was doable; not much money waiting but there was enough to justify the cost of training. Not so any longer, even with the increase in pilot salaries it will be a long time before any new pilot will break even.