>> MBA is billed as a "career changer"
This is the true problem. There's a false perception of what a business education actually provides people.
All it does is provide you with some knowledge. Whether that knowledge is applicable to your real professional career is up to the person receiving the education. And not all MBAs are equal, since there are multiple disciplines within the degree itself.
I got my MBA before the proliferation of the high priced "executive MBA", so I can't necessarily speak for the more recent MBA grads, but from my time, you didn't really acquire any real world skills from the degree. You basically acquired some knowledge that could help you understand certain situations you'd get in. There definitely was nothing that made a person behave or operate a certain way in a business situation.
The problem with the perception of MBAs is that it is somewhat conflated to the level of a profession or certification by people who don't know any better. Assuming that an MBA grad is a business expert is like assuming an English major is a grammar expert. It might be the case, but most likely, it's not.