22 year old starting his or her career today will NOT be replaced within his/her career. However, they might end up retiring as a single-pilot “captain” backed up by a much more advanced automation than what we’re used to and a copilot or ‘flight follower’ backing the captain up from the ground. I firmly believe that.

Change is gradual. In chronological order - here are positions gradually eliminated in the past and some that will be in the future:
Navigator - Flight Engineer - IRO - Copilot - and yes - one day, decades from now the Captain too.

Again, a 22 year old will be fine. A toddler? Too early to tell.