Python and Ruby aren't a suitable comparison, because they lack AOT compilers to native code as part of their canonical implementation, which is not the case for Swift.

As for access to the language implementation, Swift is Apple's creation.

The argument you made was that "Swift is a general purpose language.". Since both Python and Ruby are generally considered general purpose languages, they _are_ suitable for comparison to Swift in the exact sense that you chose to describe Swift.

I'm not trying to tell you that you are wrong. I'm just saying that your reasoning is flawed, and your arguments don't really support any particular conclusion. "Swift is a general purpose language." - OK? "I fail to see what it lacks." - Noted.

Let's only compare with native, canonically AOT compiled, general purpose languages, though. All of a sudden there are a lot of questions. Why didn't they write it in C? Why didn't they write it in Delphi? Fortran? Forth? The answer is of course that beyond being a native, canonically AOT compiled, general purpose language, different languages have different constructs and models of particular patterns that make them more or less useful for different kinds of tasks and development models.

Apple seemingly recognized that Swift was less useful than Go for the particular task at hand, and while we can't really know for sure if this was a matter of performance, development speed, personal preference of the developers etc, we can probably assume that the choice was based on taking several such quality dimensions into consideration.

I would expect Swift to have comparable performance to Go since it's a C like compiled language. Where it doesn't, Apple should probably dog-food it so they can find any deficiencies.