"What we routinely do is a skill that with a big wallet and some time my granny can learn."
Like many others in this thread I disagree radically.
As a former QFI in the RAF I know that everyone who arrived to be trained had gone through exhaustive selection procedures and aptitude tests - which had a very, very high failure rate - and I also know that some of them still struggled on the course. It's no different in the airlines, even where careful selection has taken place.
Among those who have self-selected for training, if they get a job in the first place some of them will struggle to keep a job with any respectable outfit. But even self-selecters tend do do their own selection: they drop out of training when they realise they aren't good enough.
I don't know about your super-granny, but I think mine and most others could make it to first solo in the circuit and then they'd fail on the navexes, but even if they got a PPL that would be about it. Flying safely isn't something everybody can do, and flying really well, with deep reserves, which a professional airline pilot should, is a sophisticated skill that needs a big knowledge base to back it up. And while a high level education helps, I have chopped graduate entry pilots into the RAF along with those straight out of school. It's about much more than just academic ability.