NG debate, page-8

NG is 90% established, 10% new builds so the opposite to what you posted.
20% of the population own investment properties & approx 66% are NG.

To actually get the current approx 59% of property investors invested in established housing using NG, to move to new constructions using NG would involve creating a new investment market through a 3rd party.
Most people wouldn't have a clue how to get a property built or wouldn't want the hassle.