A startup founder visa will more than take care of this 'dry powder' and get it working to increase the US GDP. Said visa needs to have a realistic "minimum savings requirement" to come live in the US & start a company (not the $1MM or even $500k required by EB-5 that put it out of reach for most founders especially on the younger side).
Said visa is a necessity because of the way human society works & the way the global order has formed. All this Capital is in the US (reserve currency). People who control it and decide how to allocate it are in the US (history). People do not like to give capital to other people who will live and use it thousands of kilometres away (oversight becomes hard).
Wishing for more tech startup founders to spring from the general US population alone is not going to solve it, and pumping all the available money into the same companies may be quite risky from a diversification perspective for the US economy.