In the long run they would have been better off just coding it all themselves with the purpose of efficiency in mind, instead of relying on work of other people

In the long run they would have been better off just coding it all themselves with the purpose of efficiency in mind, instead of relying on work of other people. The biggest misconception I've found, to date, regarding performance, is that people believe everything's fast, because a compiler/JIT makes it fast. Only a small percentage of programmers actually know how to do things right, the rest of every-thing is built up upon the same nonsense everyone gets to not just learn, but also gets to spread it even further out, creating a faulty norm everyone just accepts as true, because everyone says it's true. Fact of the matter is that, as an analogy, a garbage collector is pure and utter nonsense, because it's a bandaid to fix the issue with people having no clue how to actually handle memory properly. Instead, they believe garbage collectors are a good thing, while also struggling with it interfering when it shouldn't. To extend this analogy: Everyone would be better off just learning the simplicity of handling ones memory by ones self. Making at least ones own library for proper memory handling and management once, should be mandatory. It's not that far away from "proper memory handling" to "setting up and accessing data in a cache efficient manner" ... and further.