If people already know how to make 'human sized places' wouldn't that imply planning?
No, it's what arises from a lack of planning when you let individual or small groups of humans build structures that fit their needs without too much meddling. A shop owner builds a shop the way he wants it to be. The apartment building next door is built the way that apartment building owner wants it to be.
There's no central committee forcing them to adhere to a grand central plan that makes everything look alike. That's how you end up with varied, idiosyncratic architecture that has personality instead of the vast, lifeless spaces that were designed by committee to be all things to all people and end up being nothing to no one.
There does have to be some central coordination to help mediate disputes and ensure one person doesn't infringe too much on others, but it should be minimal.
Your comment seems to be about aesthetics, but it makes no sense. Do you think shop owners usually build the buildings they inhabit? No one mentioned a uniform look and it has nothing to do with anything. It is completely orthogonal.
Think: if you didn't have to worry about work or money, and could live 'anywhere' - where would it be? Almost all of the aspirational places are not 'planned'. They're generally made before cars and therefore 'human sized'.
Do you fantasise about living in the suburbs (ie generally more planned?) probably not. People live there because of space, lower prices, but not because they're otherwise idyllic.
Some 'nice things' we get from 'planning' (more consistent rooftop solar) would be overwhelmed by all the inhuman artefacts.
Most places in W. Europe offer 'good living standards' - beautiful and 'postcard idyllic' situations that go on and on and on. (The jobs are lacking, but not civic beauty).
If we can somehow figure out transport without cars, and get a lot of the ugly infrastructure 'out of the way' - that would be nice. But otherwise, we already know how to make 'human sized' places.
Edit: I should add, nobody wants to move to such planned cities, unless they are implored by their condition to seek opportunity, i.e. jobs. People in happy situations don't seek this out.