The main reason is that Play is really, really important to making us better humans, so humans really, really like to engage in the form of Play no matter what

The main reason is that Play is really, really important to making us better humans, so humans really, really like to engage in the form of Play no matter what the content. One of the cultural challenges that humanity faces is making Play align with bigger goals -- for example, if you love carpentry, you might volunteer with a shelter building program for all the "wrong" reasons, but yet... houses get built and (probably most important) carpentry skill gets developed in humans. I would agree that Eve might be a complete waste of time, along with soccer and chess and (my favorite) Dungeon Crawl Stone Soup, but I think the instinct to Play is very real and very productive, it should just be channeled intelligently.