Much of London is still owned by large landlords (estates) that don't so much sell their property as offer very long leases (99-125 yrs). There was a recent exhibition here about them (see enclosed publication).
The basic contention is that, by owning a lot of contiguous property, these large landlords can engage in behavior that maximizes (or seeks to) the appeal of the area as a whole, rather than getting the most for the least out of every single building. I definitely recommend reading the piece before posting comments.
I think Jaws should find this particularly interesting because it is in some ways an approximation of his 'private cities' concept. Lifestyle centers and NU developments could also be considered descendants of this system, in some ways.
I was working on a small essay on how it probably makes sense, in a city, to have a mix of public, large private and small-scale private property...and this comes along. What do you guys think?