Most (good) developers are definitely at least partially self-taught, but those who are employed in the industry also tend to possess, not necessarily a CS degree but at least on in a related field.
It pays to have a good programmer with degrees.
All of those hasn't been a factor in if a developer is good or not. It's when they "hit a brick wall" and give up. The best developers ask for help when stuck and help others when they're stuck.
There are very few CS courses I took at the university that prepared me for the real world. I'm sure there are certain fields like AI, DB algorithms, Math/Science applications, compilers that benefit from formal academic training but for the most part being logical and a a good problem solver are the most important skills.
Of the best developers I've worked with/know, only 1 has a CS degree. One has a liberal arts degree IIRC (works at Netflix), another is a college dropout (works at Google)...and the one with a CS degree has a tendency to overengineer systems with great flaws that the others I know wouldn't do (tries to be too clever). Myself, I have a MS in math from a top 15 program (PhD dropout).