If an experienced Airbus Captain/FO , wants to join , say Ryanair, they pay for the rating to work there.
If a similar experienced Boeing Captain/FO wants to join easyjet, they pay for their rating to work there.
If an experienced Airline Captain joins a legacy carrier, they start at the bottom.
Companies now want pilots ready trained, on a plate. So who's actually doing the training?
Ultimately, its the individuals themselves, at some point.
Therefore, there's no shortage of experienced crew, simply its not appealing to now change employer with the constraints of the modern
day recruitment processes and associated financial terms placed on accepting employment.