macrocephalopod

This is a good question! Some possible answers - 1. Infrastructure that is too expensive or too hard to build yourself (eg colocation, low latency data feeds, compute clusters, fpgas) 2. Data that is too expensive or simply impossible to buy (eg historical tick data)https://twitter.com/mobile_mm/status/1373427747901542402 …

Also, the variance of even a very high performing strategy is a lot for most people. Simulate a bunch of GBM processes with returns 2x vol. Observe how often and for how long they are underwater.

Very good point! Even good strategies have down or flat years, and you still need to pay your costs in those years, plus your rent/mortgage/living costs. At a fund or prop shop most of your costs are top line and you still collect your base in a flat year.

A salary is really the best "carry" available