When I was growing up, I spent many summer days struggling to shove a bulky Toro mower through the thick mat of grass that was my yard. That was my main weekly chore. I pushed that same mower around the neighborhood with my buddy, Mike, hawking lawn-cutting services for $10 a yard. I've noticed something peculiar while driving around town in recent weeks: Though it's summer, I've yet to see a single kid out mowing a lawn. I don't see any kid-produced signs offering mowing services. I see teams of lawn-maintenance workers neatly tending yards...but no kids.