Economy is a measure of the movement of money. To spend up the economy, we have to keep the money moving.

Isn't the problem hoarding?

Everyone hoards. Rich people hoard wealth. Right? Not a moral statement. Preferential attachment (winner takes all) is just math.

The problem for society (the economy): we have all this unproductive capital (wealth) lying around, AND we have all this work that needs doing, BUT it's not efficient for rich people to manage a large basket of smaller investments.

So to grow the economy, we need better strategies to keep the money moving. Progressive taxation has worked in the past. YCombinator seems to have found a new way to match investors to opportunities more efficiently.

(Sorry, being a simple bear, I don't know of any other strategies. Maybe "Buy Local", which keeps the money moving in smaller networks.)

To me -- a person who barely understands "money", finance, economics -- it's really just that simple.

Keep the money moving.