To complete a four year degree requires a commitment, a life-altering personal financial cost, and most importantly, a willingness to abide by the rules and procedures of a complex organization, even when they don't make much sense or directly contribute to the core competency. It shows a willingness to submit to authority, a willingness to get often arbitrary work done on schedule with acceptable quality, and other traits and experiences that matter a great deal for becoming a functional employee in a corporate workplace.
Coding competence is nothing if the coder can't follow instructions, complete work on schedule to spec, or tolerate doing things that seem arbitrary and useless.
A degree isn't about proof of being a viable programmer. It's about proof of being a viable employee.