It is not at all uncommon for source codes to be kept under wraps; it is akin to having a secret recipe and not divulging the ingredients, proportions, and means to make the meal; without secret recipes, KFC would be out of business. Basically, what is at stake is intellectual property and the ability to defend it; if you notice, the most complaining in the industry itself comes from the competitors of MS, but that is how it always is, no matter what the business or industry; the best response is to make a better product than the one they complain about, or as it is otherwise known, "build a better mouse trap"; I am sure of one thing: if an MS competitor did devise a superior OS for profit, they would be just as zealous about protecting their source code...
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