[forgotaccount3]

> What part of your idea was supposed to stop that happening

The part where people see their money burning away paying maintenance and tax on deteriorating assets.

Why are people holding assets unused?

Because they don't believe that the city will allow sufficient development to allow them to purchase like-assets in the future if they chose to reinvest and the carrying cost is minimal because council taxes are trivial relative to the value of the asset. If my research is correct, Kensington council taxes are under 10k USD per year.