While I understand your point, the danger in this over simplification is that it encourages brute forcification. If 10k hours were only enough, our typing speed

While I understand your point, the danger in this over simplification is that it encourages brute forcification. If 10k hours were only enough, our typing speed would keep increasing. But that's not the case; to improve you need to be challenged with a higher skill level requirement. For example, if you're at 100 WPM, use a typing tutor that requires 110. Otherwise you'll just stargnate.