Because people claiming that MBA are the problem is not evidence that MBA are a problem. Obviously some companies will make missteps and when they do it will be managements fault (because, surprisingly, management were in charge). On balance, the powers that be believe MBA are more likely to lead to increased profits than losses.

Besides, someone is always going to be complaining about management. That is one of the pitfalls of management - everyone seems to be an expert at running a company except the people who actually do it.