It's really a matter of time invested. I should probably take that back about self-trained programmers being better. Instead, what I should say is that self trained programmers are "usually" more interested in programming, which is why they started teaching themselves. If you like programming you will do it a lot, especially outside of class, and that will give you a lot more experience very quickly. On the other hand, I have a number of friends who just started programming in college. Some of these quickly became enamored and did as much outside of class as I do. Although they started behind, I have no qualms that they are as good in a couple years as those who taught themselves. Also, be careful with my statement -- I never said that those who started programming in college will never be as good as those didn't. Instead, my point was that, right out of college, many people will only have 4 years experience (mostly in classwork). In contrast, I am one of a group of people that I know that had contributed to a number of large open source projects and other things (like kernel hacking) before college even started. I'm sure that the smart people who major in CS will have no trouble with doing that in a couple years time, but I'm hesitant to say that 4 years of teaching assignments actually prepare you for programming in industry.

If it's anything beyond the sheer amount of time, it's that 1) people who don't teach themselves will probably be at a disadvantage given how much new material regularly needs to be learned, and 2) there is likely a window during which time picking up new skills is easier. Learning programming is probably analogous to learning a musical instrument, a new language, etc., in that people seem to pick things up more quickly if they start while fairly young. While learning a new API or something once you've been programming for a while is largely a matter of time, but there are Big Ideas that need to be learned upfront. I didn't mean to imply that it's impossible to learn them, just that it's harder.

That said, my main disagreement was with your comment, College is probably too late to learn the fundamental techniques and mindset of programming - this was very reminiscent of the dialogue many religious groups will say about instilling church fundamentals, hence the reason I used the word 'indoctrinated', along with its connotations. As for the mindset of programming, there are many fields who are surprisingly close to the needed mindset, and still, it may be largely a personal matter in as much as some person will have the needed mindset no matter the field they choose.

I certainly have no argument over the amount of time needed to learn programming, and definitely agree that starting in college is much more difficult. It is just that I have been impressed by late learners to programming who came from other fields (mathematics/physics/economics being some of the best to draw from), and as such I can not underestimate the ability of another who came to programming later in life.

Have a nice weekend.