In all fairness, the manuals that filled a whole shelf documented a lot of major applications. On my desk right now, I have a copy of the O'Reilley book on Subversion (a source control system). I have another book on Emacs. And so on. ALL of those things were covered in that shelf.
Over the last few days, I have been surveying the WWW for criticisms of Common Lisp. The two that I see most often are: (1) it's too big, and (2) it's missing so many important features like threads, sockets, database connectivity, operating system interoperability, Unicode, and so on. Ironic, no?
It is really too bad that Common Lisp was not defined as a language core, plus libraries. We did originally intend to do that (they would have been called the "White Pages" and "Yellow Pages"), but we were under too much time pressure.
There is no question that Common Lisp is a lot less elegant that it could have been, had it been designed from scratch. Instead, it had two major design constraints: (1) it had to be back-compatible with MacLisp and Zetalisp in order to accommodate the large body of existing software, such as Macsyma, and (2) it had to merge several post-MacLisp dialects, in a diplomatic process (run magnificently by Guy L. Steele Jr) that made everyone reasonably satisfied. It was quite literally a design by committee, and the results were exactly what you'd expect.
But the imperative was to get all the post-MacLisp implementations to conform to a standard. If we failed, DARPA would have picked InterLisp as the reigning Lisp dialect, and we would have all been in a great deal of trouble. (Look where InterLisp is today; actually there's nowhere to look.)
You wonder how other people learned to use Symbolics machines. Some of them took courses - we had an extensive education department. Before you say "that proves that it was too complicated", keep in mind that the system was very large and functional because that's what its primary target market wanted. We did not get feedback from customers saying "make it simpler"; we got feedback saying "add more features, as follows". I bet the people who maintain the Java libraries are rarely asked to remove large amounts of the libraries.
I'm not sure what the reference to Steve Jobs is about. Look at how many features the Macintosh has now. It takes a long time to learn all of them. Their documentation is much shorter because they don't give you any; you have to go to the book store and buy David Pogue's "The Missing Manual" books.
I admit that some (not most) of the complexity was gratuitous and baroque, but not because we liked it that way. The complexity (mainly the non-uniformity) of Common Lisp was beyond our control (e.g. the fact that you can't call methods on an array or a symbol, and so on). Some of the subsystems were too complex (the "namespace system", our distributed network resource naming facility) comes to mind.
In summary, I'm sympathetic to what you're saying, but the reasons for the problems were more involved.