Perhaps with the exception of space weapons, none of those would pay Jane Street-tier salaries.

All I'm saying is that I wish our economic system were set up such that people with the mental aptitude to work at a place like Jane Street could earn commensurate salaries for applying that aptitude towards problems with much greater positive externalities than proprietary trading. Alas, it is not so.

It’s incorrect that proprietary trading has negative externalities. It’s also exhausting trying to explain that to an audience that has fundamental misconceptions about economics, financial systems, and monetary systems, so I don’t think I have the energy today. Hopefully someone else will and add to this thread.

I never said it has negative externalities (whether it does or doesn't is a totally separate discussion), only that its positive externalities are certainly much less than some other fields that employ commensurately smart people, e.g. healthcare or climate change research.