Realistically, a laid off pilot with a seniority number and a promise is looking at 3 - 4 years out of the flight deck, depending on
1. The strength of the recovery.
2. How close to required numbers his airline will be at, did they overshoot or undershoot with the layoffs.
3. His position on the return list.
4. The airlines ability to train, check and return people to service.
A suitable pilot with experience and a decent type rating, without a queue number or bottom of the list could easily be looking at 4 - 5 years.
New licence holders easily 5+ years.
A tiny minority were lucky and got previous jobs back, such as the RFDS, or went to REX for the B737 but most have ended up with jobs well below their qualifications and ability.
The result of COVID could be a significant shortage of pilots at particular career points in the decades ahead as a gap of years when little to no training was undertaken moves through the system. First there's few suitable applicants for F/O jobs and few training schools, then there are few F/Os with the required experience to upgrade then there are few experienced captains. A future pilot in primary school today could be looking at a wide body command with QF on the East Coast in under 10 years.