|the people who programmed Windows are not the best programmers|
"Best' is an ambiguous word.
- Best at writing high performance code?
- Best at writing elegant and concise code?
- Best at making shed loads of money out of their code?
First and foremost, commercial
software development is about making money.
I don't mean you should just throw any old rubbish together and flog it, but process and good practice are there to make software development more efficiency, so it costs less (time, effort, energy, and esp money) to develop an application. Not for their own sake, like they are in some parts of academia.
And while I'm certainly not saying that doing well in an informatics olympiad -- or whatever -- is bad (it's very good!), it isn't the whole story when it comes to being a good (or even one of the best) professional developer(s). There's also the business domain to understand, and internal politics to contend with, etc.
(Professional includes, of course, the unpaid professionals who work on serious open source projects.)