I'm not sure if that argument holds water. You have Azure which is hugely successful, and Linux is still not anywhere close to becoming a standard desktop environment beyond the type of people you find on HN. Microsoft contributes quite a bit to Linux now, because they see the future. Becoming a leader in open source gives you the ability to steer where technology goes, and Red Hat definitely was able to play that hand as well (but under IBM seems to be losing quickly).