I can't comment on Swift as I've not used it but I can say that Go is more than just a language. It's the embodiment of Google's experience running large engineering teams. So many of the decisions in Go--its simplicity, the formatter, the opinionated directory structure, static linking, no special build tools--make life a lot easier for teams. Again, I haven't used Swift, but I don't get the sense that this was one of its design priorities. I've been wrong before though :)