I have the answer to my own question.
Did you know that if Walt Disney were alive today, he'd be 109? But that's beside the point.
Recently I read this book called the Art of Walt Disney, and it was from that book that I learned about how things went in the early Disney.
Walt only supplied the ideas, and he always had lots for his artists. In fact, Ub Iwerks drew Mickey, and Walt supplied the Mouse's personality and voice.
Disney was a man of unlimited creativity, and of course with him the studio was never lacking.
Basically, what I'm saying was that when he died, Disney as they knew it then died. They were able to keep the fire going for awhile, but eventually the Studio would collapse. Disney was the core of the Studio, and when he went, the spark that lent Disney its originality and prowess also collapsed.
It's too bad Disney died at age 60, because I wonder what he would have done with CG animated stuff.
If you doubt what I say, read the book I just spoke of.
Peace.