Earlier quoted context omitted.
Why are you discounting the importance of video game skill? With esports people are making a living on it. Person B is specializing in a skill and mastering it. Person A is a jack of all trades and master of nothing.
Playing video games for that long destroys your body, I personally know from experience. Exercise also makes you better in every other thing in your life as well (including video games).
It isn't only video games that get hit with this; for example, in my experience ballerinas get a lot more faux concern about "destroying their feet" than, say, sprinters do, never mind that they have pretty much the same foot injury profiles.
(See also: sitting at a desk for eight hours to play video games is obviously bad for you, but sitting at a desk for eight hours to type reports for your employer couldn't possibly cause you any issues that said employer might be on the hook for.)