[esonoi]

Not entirely true. Two things to consider: 1. Public sentiment. When Goldman Sachs open sourced their collections library on GitHub, it gained marginal traction (opinion: seemed more about PR to attract tech talent). When it was adopted by the Eclipse Foundation, usage rose by a non-trivial amount (based on usage stats from mvnrepository that aren’t other eclipse projects). 2. There was a massive hiring frenzy, and their due diligence regarding IP was non-existent. Garden leave doesn’t compensate for ‘strategic’ systems. Apart from “competitive advantage”, when you have someone as tenured as he who shall not be named, you mitigate the risk of being sued by not making it obvious you’re cloning a system developed for another firm.

Bulge brackets are more risk avoidant than smaller firms, like hedge funds. Today, we have LMAX disruptor and Real Logic’s Aeron (basis for Akka Remote) due to their liberal policy towards open source.