It doesn't work like this... If I have $10k worth of gold and I sell it, does anything actually change in a meaningful way?Quote from power:
But if today, USA sells $23 Trillion real estates, USA economy will get $23 trillion cash or money.
Asset value = Cash.
So Asset value will flow into the economy the moment the asset is sold or realised.
Smaller example, if you have Gold worth $10,000 (asset), you will earn cash $10,000 when you sell it.
As pointed out by others, GDP is a measure of value added, not of total value.
Unless you are talking about the total value of all the assets in the world, which is largely irrelevant, since it's kinda immeasurable.