I always thought the "imminent pilot shortage" doomsday-predictions-that-never-really-materialize were pretty much orchestrated by manufacturers and airlines alike to have access to cheap labour.
I still think the same. BUT:
Since we can pretty much discount there WILL at least be 1 efficient vaccine, let's go with the 2024 "return to 2019 levels" scenario in terms of worldwide pax numbers. I believe markets such as european and US domestic short-haul will recover quicker though (summer 2022) despite not overly favorable macro conditions. Capacity will be there perhaps revenue will take a bit longer. Everyone wants to gain market share.
If most of the VLAs A380s, B747s and some of the older B777s etc. are decommissioned, it means to match the number of travelers you need roughly double the airframes (B787/A321XLR etc) or at least 1.5 the airplanes.
Assuming that is true that there was a relative shortage of EXPERIENCED flight deck crew in 2019, that means unless they all of the sudden go single pilot there will necessarily be an experienced airline pilot shortage between 2022 and 2023. Remember that it takes years to reach the necessary experience to become a Commander even a senior first officer and particularly when people are flying once a month these days they are not really accumulating experience. Also remember that people keep retiring (confinement does not stop aging) and fresh cadets out of school are not building meaningful hours.
Unfortunately, in Europe, I'm afraid most pilots will not manage to find alternative and successful careers outside aviation unless they had a previous education and experience and will pretty much be forced to return to flying.
That's how I see it.