I'm not saying "because they are lazy!" but, I think it is a combination of a large portion of people wanting a large piece of land and planners just using cars to fill in the gaps on convenience. I do think that a lot of folks would prefer to have better public access to things like parks, it would mean a lot less personal maintenance. But this is a hard sell for some people that have a vision of a certain lifestyle. And for planners, they are probably working with some very tight budgets and timelines to deliver. It is just easier to produce yet another grid of McSame because they know there is an audience for it and it makes their jobs a lot easier.

I do wonder where this will lead in decades down the line but for many that is not an issue they are considering.