I like to think of this quote as being joined at the hip with another of Warren Buffett's quotes.
"Read 500 pages like this every day. That's how knowledge works. It builds up, like compound interest. All of you can do it, but I guarantee not many of you will do it."
Well, yes, if you have been reading 500 pages a day - and the anecdotal evidence suggests that a lot of these pages comprise 10-Ks, 10-Qs, regulatory reports and such - you might be able to get really good at picking stocks after 50 years of adhering rigorously to this regime.