"If I had more time, I would have written a shorter letter." -- Voltaire
The problem is that, in many (most?) professional settings, the developer is under huge pressure to get shit done. Not get it done perfectly, not done beautifully, but just done in the first place. We rarely have the leeway to spend extra time refining existing code, existing features or bugfixes, to make them prettier. It's gotta be done, and it's gotta be done yesterday because maybe some other part of the project is blocked because of it or some customer paid for it and it was supposed to be done last month or it broke and why the hell isn't it fixed yet!?
Some projects, I daresay mostly open-source projects, can afford to be detached from the pressure of deadlines that corporations require, and reject code that isn't to their quality standards. Sadly, that's not the case for most of us.