how will that help the people in existing areas? Or is the magic money tree also going to buy their houses off them so that they can move to the new brownfield housing estates?
Well first the term "housing estate" is not quite the best. Perhaps "People Hubs".
But anyhow. I believe that people are reasonable by nature. The prospect is a simple one. And easily understood....that our present system of land allocation is causing great harm to the environment.
"Carrots" would seem natural. The new housing and amenities would be very pleasing and people would naturally want to live there. Done correctly, the massive savings realised by a more rational system would allow for reasonable pricing and quite nice surroundings. Safety, green spaces and urban forests would make the new transport-based living areas attractive.
Again, just outside the borders of these new transport-based hubs would lie a newly revitalised countryside. Perfect for bicycling and walking and even camping. Pleasure gardens and things like that could be brought back. Open-air concerts and exercise trails and such. Boating and sailing.
With good dedicated rail-based, electric transport travelling to your work site would be quick and pleasant, and being more condensed, these habitation hubs' shelters would be more readily available than is now present on rural bus lines.
The key is to make them very pleasant and affordable and safe. With access to nature and culture. Who would not like to live there?