I can tell you why the above mentioned airlines weren’t hiring (but in reality they actually were. I personally know of 3 CX crew who left in 2018 for QF). Those airlines weren’t really expanding to new destinations so they’re just replacing staff who were retiring or chasing the money as elsewhere.
When you have countries like AU, NZ and US putting pilots on their “shortage” immigration list and issuing respective visas like hot cakes, it’s because they’re running on data, a lot more substantiated, verified data not anecdotal evidence, which you seem to be running on.