I would think in the summer, if you drive into many subdivisions on trash day you'll find bags of grass clippings by the curb. In the fall, drive through and you'll find bags of leaves. You could also contact any tree service near you and ask if you can have their chipper stuff. Most of them pay to dump it and would be glad for someone to take it away for free. Contact lawn care companies (mowing services) and ask if you could have some of their clippings. Contact your city arborist or public works dept and ask them what they do with the grass clippings and chipper material from their public landscape maintenance. I mean there are options...
In areas with water that falls out of the sky and green vegetation around, these ideas would be great. In my desert area it's xeriscaping all the way. Hardly anyone has grass because no one can afford the water bills. And the city is too far away to deal with. I'll stick with my current management program, which is pine shavings bedding + whatever garden stuff I can scrounge, that I change out and compost 2-3 times a year. It's not ideal but it works.