I think a lot of the popularity of athletic sports comes from the fact that a viewer has some sort of stake in their team, such as pride for their city or country, i.e. the psychological aspect of "we're better than you." At least for myself, I enjoy sports, but only if I have a stake in the team. If it's just two random teams that I don't have any attachment to or opinion of, I tend to not be interested at all even if it's a sport I thoroughly enjoy watching when my team is playing.
If video games are to have success on a larger stage, such as broadcast television, the average Joe is going to have to care about it. I.e. "Hey, the Seattle xxxx DOTA 2 team just beat the $#)(% out of San Francisco, etc."