It also relates to the brain-body ratio for species, because investing in intelligence works for them - it says something about that species' environment/niche, and not just the species itself.

If games now provide the best gradient of reward for effort...

Another solution is to change the problem: what if games did provide a survival or reproductive advantage? Quite possibly, social media already is, being better connected has long been an advantage ("it's who you know, not what you know").