It can seem very simple - neighbours work together to solve the immediate design challenges of their neighbourhood where they live, pay taxes, and interact (or not) with each other. But it isn't simple. Not at all. We aren't in the habit of tackling the issues we face together. We're great at autonomy, fantastic at looking after ourselves. But some things just can't be tackled that way.
My experiences living in Canada seem very similar to this UK example. I like the idea of DIY planning and development for adjusting things toward a better solution. We need the specialists but they should never be able to do their work in isolation. An even if one solution worked at one time, an ability to evolve over time is essential to our design work at all levels.