I started to make much more money by just spending the same amount of time writing enterprise software. HFTs made it very hard to find a moat in technical trading, I don't believe you can beat them at their own game today; I especially don't think you can just make something and get passive income from it - that was never the case, it was always a job, though very flexible one.

I switched to stock picking based on the premise that the market at large might be momentarily irrational because it doesn't have the same insight into the tech industry as I do - e.g. I made good profits on AMD between $30 and $150, Nvidia $100 to $400, some medium term trades on Supermicro and TSMC.