Rome, Great Britain, and the US
Infrastructure that facilitates trade and spending on forces to protect said trade routes.
That is how we and the other two spent our way into prosperity.
And it was done quite a long time ago, by, as I pointed out,
by private industry and not by government entities--not in modern times, in any case, or not successfully in modern times. Are you familiar, for example, with the history of the first American transcontinental railroads? Which, I might add, are completely irrelevant now?
Of course infrastructure facilitates trade--and it's private industry that is responsible for infrastructure buildout in the most prosperous modern nations. That includes roads.
But once the bridges, tunnels, railroads, and canals are built--again, by PRIVATE INDUSTRY, not by governments--that's it. They add no more to economic growth beyond that facilitation. You can't just keep building bridges, tunnels, high-speed rails, and the lot and expect to have a vibrant economy. Bridges to where? Bridges to nowhere? How many bridges are needed to ford a river for any given economic region?
This argument is a sideshow. As I said, no one disputes that you need a stable political situation for private industry to do well. But that's all. Spending directly by done by government, throwing money at banks and businesses, especially when done by the most central government of any nation, is Keynesian crap and it fails miserably, and
that's the spending we're talking about. The money needs to simply be left in those businesses hands to start with and THEN we will have prosperity.