This comment cuts to basic point. Positions vaguely labeled "Senior AI researcher" are for research directors, not engineers. Taking a Udacity ML class and "teaching yourself some linear algebra" and Python is similar to achieving basic literacy in foreign language - you may be able to ask for directions, but try writing a novel.

Any job that requires significant expertise will command salaries at the top of the curve. Corporate litigation and IP attorneys command 400k-2m salaries, yet we don't get articles about IP lawyer bubbles, because the competition is vicious.

More interesting highly paid salaries to debate:

Neurosurgeons Cardiologists Attorneys Plumbers Consultants Investment bankers Traders Product Managers