I suspect there may be some sort of hype in the AI area regarding salaries. Sure, there are a couple of rockstars, but I suspect that competition is really intense and compensation in ML area has an even more acused power law distribution than general vanilla software engineering that doesn't face as much pressure from maths, stats and other grads that look for a career to apply their quantitative skills.
I think that in the real world paradoxically math skills are easier to find than solid software design and development abilities. It may stem from the fact that the first one is taught quite well in school while the other one is more about individual learning and sometimes a contrarian stance to the system (can be reflected even a somewhat childish "I'll learn Haskell because the OOP and Java suck!") which is harder to find and therefore, more valuable.