Consultants are like Power Points. They are easy to create and subsequently there are lots of them.
Most PowerPoints presentations are not very good, like most consultants.
The effort and training needed to become a consultant is a lot less than the effort needed to become a developer.
The quality of person in any role makes a big difference because most of the work done when creating software is thinking and problem solving.
The bigger the number of people hired, the lower the quality drops.
Like technical debt, the best policy is to keep it out,