I remember one of the big things you would hear about visiting WDW when it first opened was you had to make a reservation months ahead of time, it was almost a special treat if you got to book Poly or Contemporary.
I remember in late '83 my future wife and I decided to go to WDW for our honeymoon, our wedding was to be in May of '84. Had never been so didn't know much about it. Called Disney reservations to see about booking a Disney Resort and told, even calling 7-8 months ahead, only the most expensive room at CR was available. Wound up staying at Buena Vista Palace.
There was a book which came out maybe 10 years ago now, not really sure, name of it was "Storming the Kingdom". It was about the family fight over Disney about the time Eisner took over. One part of the book discusses the fact Disney was not building any Disney owned lodging. One of the Disney board members involved in the real estate business had to convince the rest of the board that having more disney lodging on WDW world property was a good thing.
So in the very late 80s early/mid 90s new resorts were being built all over WDW property so lodging money would flow to Disney not off site hotels. Seems like a no brainer now.
Phrank