> Most people would see this as wasteful NIH but I'm convinced it was a net benefit for them—they managed to be so productive in an absolute sense and especiall

> Most people would see this as wasteful NIH but I'm convinced it was a net benefit for them—they managed to be so productive in an absolute sense and especially on a per-engineer basis because they were willing to build so much themselves, not despite it. It paid off for them, but I would say it's a risky move in general - it is very easy to get sidetracked with failed projects that have nothing to do with the business. There are many examples - Uber's internal chat system, etc. Others tools were more a necessity, eg the OCaml build story was not great back then. Investing in OCaml itself was a calculated risk. Also I wonder how things would be different if they were starting today, where there are more mature tools in the space.