The order of magnitude point is just wrong. You might argue that it's harder because it's essentially software development and a lot of applied math. But that certainly doesn't account for orders of magnitude difference.
I'm a java developer and during my first 3 years I was able to investigate bugs not only in my code, but inside jboss or hibernate ORM; I can look up core java code and understand it just fine.
How many of the ML self-taught crowd can write framework-level code, or debug a ML algorithm bug?
Fooling management wanting to get into ML with some scikit code is easy, mastery of ML is orders of magnitudes harder than mastering a programming language/frameworks.
This isn't specific to ML though - I don't see why the number should be different from the number of self-taught web developers who can write framework-level code.