Partly because a lot of them WROTE that baloney or else don't care. I say I'm suburban, but its a very urban suburban. Most of my neighbors are up an coming professional families. If they have kids they might have a small veggie garden for them, but other than that, their yards are the kind of thing they leave to their gardeners and landscapers. Plus, I think we're currently the only house with any significant numbers of trees close enough to anything to cause any damage if they fall. Our neighbors may have 40-50ft oaks like we do, but theirs are all a good 50-60 ft away from their house. They've got lawn, we've got scrub.
Fact is I sort of understand why the tree law is in place. Chopping down multi century old oaks is not something one should be able to do on a whim. We need the shade and cover and there is the matter of keeping your property nice for the next person who gets it (and this isn't the kind of place where houses get handed down generation to generation so "my land, my right to do whatever I damn well please with it, doesn't really work logically." And trees that old deserve respect (I actually conducted funeral rights when I was kid for one of them, since it WAS probably going on 8-900 when it went (how long does it take oaks to develop that "onion bulb" base?) I just wish they'd add a loophole for "emergency" situations. And to be fair I can't seem to recall any case of anyone ACTUALLY bringing suit for a tree fall. Even back when I was a kid and our pine fell on the babysitter's friend's car, I think the car's insurance covered everything. And the rules really only apply to trees tall enough to make a difference in the shading (we could take down those crabapples whenever we wanted since they are shortish. We're just too lazy to get around to calling the tree guy (though we did hack half of the healthier one off when it began to split and endanger one of the power wires)
But it is all academic. Here I am, and here I will probably remain for the future.