Both AOPA and the EAA have been VERY active in promoting "sport" aviation. They even pushed through a few new license categories for pilots and aircraft to make it significantly easier (and cheaper) for a new pilot to get into the air.
I don't have the exact numbers, but under the new categories, it's possible to get a limited license with about 20 hrs of instruction and buy a fully certified aircraft for under $20,000. That brings aviation access down to the common man, and it's been a key push, both with legislation and with the overall industry, to make that happen.
I personally think it's great. The sport pilots are restricted from flying near big cities, but in the vast majority of the wide open US they can pretty much do whatever they want as long as they adhere to a few simple rules such as flying planes with restricted power and weight, etc. It's sort of a middle ground between ultralights and traditional general aviation.