You can't argue 'every field I look at is not in decline'

I never said that. I said the evidence was mixed.

More generally, your median point applies to the self-assessments too: even if self-assessment is completely random and actual field performance is random too, you'd still expect a quarter to be - by sheer luck - above the median in actual performance and self-assessed performance. So if a full quarter are optimistic and outperforming, how did you miss them?

By "self-assessment" you mean forum posts and personal blogs? Well that was exactly the point I made originally. It seems the is bias that causes that vast majority of self-assessment to pessimistic, even when field performance is good.

Someone drowning has too much water, and someone dying of thirst in the desert has too little water; is it really so absurd to say that 'some people need more water, and some people need less water'?

If I tell you "Sarah will get more water next year.", it would be absurd to tell me that that is a good thing or a bad thing, unless you have information about how much water Sarah already has. You can't say that Korea's stricter laws will be a bad thing, unless you have information suggesting Korea's. You can't say that Australia's more lenient laws will be a bad thing, unless you have information suggesting Australia's laws were already optimal or too lenient.

Now maybe you have this information about Korea, but I doubt you have it about Australia. And I doubt the that backpackers have this information either, considering that they don't even seem to know about new deregulation.