Let me see if I follow this:
Private investment isn't necessary? And basically the ideal system is a middle class spending money on products and the government doing the investing?
See if you can find the hole here. It shouldn't be hard.
For the record, net investment as a percentage of GDP drops in all nations as they advance from basic agrarian systems into high-tech.
P.S. I want to see some sources on those numbers. Particularly "investment" levels in 2000.