I can show you a lot of teenagers doing the same but playing football(soccer), less hours at least, and even pushed by their parents with the hope that some of them will be the next Messi, Xavi or Ronaldo.
If we were to look at football and basketball sports' effect on children, and how pervasive and time-consuming it is to normal teens/young-adults the same way we do when it comes to "e-sports", then we'd be positively disgusted (a bit of extrapolation there).
Furthermore, most traditional sports also improve one's physiological health. This is not the case for e-sports where one is simply sitting in a chair all day. I can understand why a parent would be more concerned about their kid that doesn't leave his computer than their kid that plays three sports a year.
But in both e-sports and traditional sports you have the risk of sacrificing too much for the sake of the game. I have known many athletes in both camps that have done this.
In fact, it seems it does. http://www.scientificamerican.com/article/does-heading-a-soc...
Yeah, I probably could just do weightlifting and cardio on their own (and will sometime have to transition to this) but to be honest football is my primary motivation for doing these things in the first place. A lot of competitive athletes make a successful transition from competitive play to less injurious activities after their careers and are none the worse for it. (Minus NFL concussion cases...)
There are also intangible benefits to playing competitive sports. Being part of a team, working hard to achieve a goal, being challenged, pushing your limits, pursuing something you're passionate about, succeeding at an elite level... Sports can give you unique experiences you'll treasure for your lifetime and also shape you as a person.
It really is an optimization between the all the trade offs. Every year I have to weigh what the sport gives me and what the sport takes away and decide whether it's my last season.