It's all over the place, and it changes with the times and economic cycles.
Keep in mind that any sort of internal consulting (or whatever it's called - corporate development, strategy, etc.) is a cost center. That means it's not a group that is tied to a specific product or service line - it's job isn't to help build a product/service, or to sell a product/service.
And like any cost center, it's always hard to justify your existence. I know the job sounds cool to many MBAs because it's all "big picture" and appeals to their God complex, but more often than not it's really a temporary thing (a glorified rotational program that cycles you through and spits you out into a business unit), or it's the servant's quarters that service the executives so to speak (which they will promote as "you get exposure to the highest levels of the firm" - but you're basically there to crunch numbers and provide research for them). Better to be the Duke (head of a business unit) than the head butler (Corp Dev head) to the King and Queen if you know what I mean.
The political power in any business lies in the jobs that are revenue generating - jobs where you are either making the product, or selling it.