tl;dr investing in stocks is not investment in technology development.
There is a fundamental flaw in the author's analysis. The $2T invested in stocks is arbitrage--the investor believes that a return will be gained by the movement of a price of the underlying stock. That $2T hasn't gone away, and the underlying "asset" is still very liquid because there is a market. i.e. $2T today, $2.00001T or $1.9999T tomorrow.
The purchase of a stock on the open market--the exchange of currency for the stock asset--may result in a change in the company's balance sheet, or it may not. Buying $10k of IBM does not directly put $10k into IBM's coffers--but the purchase may result in a slightly higher or lower market price which results in a slightly different balance sheet.
Spending money on technology development and buying stocks on the open market are two very different things. VC's take high risk in the direct purchase of stock from a small business to help them develop technology. But those assets are not liquid, the chance of a ROI is quite small, and there are very few of these types of investors that are able to invest in this fashion. Most "stock investors" are either not qualified or don't have the stomach for this type of investing.
