Most tech work is not particularly novel at a technical level. Very few services have any sort of massive advantage in the technical IP. Some of them might have advantage in customer/data analytics, but most advantage is in the idea itself as well as being gaining the market and brand. Another firm can't just go "Ah, today we'll knock out X new app and take 50% of the market"

This is not true in trading. If I go take my strategy/forecast and go to a competitor, I can just outright take the same opportunities that the other desk was taking (to a fairly good approximation). There's no real branding/network effect - it's a pure quality of execution business.