You can no doubt be extremely successful without being the best at something, or particularly intelligent.

But becoming "one of the best programmers ever" would require an extremely high level of computer science knowledge and understanding (at least in my eyes), which boils down to many different disciplines of mathematics. This would obviously correlate with high intelligence.

I'm of course using a generous interpretation of the word "programmer" - someone who can analyze problems, design, and implement efficient solutions to any number of problems in computing.