It's important to note that Microsoft's choice of Go for tsgo was because it would be easier to port the existing TypeScript codebase due to the structural similarity of TypeScript and Go. If writing from scratch, they likely would not have chosen Go.
Which is not to say that Go can't do well in tooling. Only that Go was not necessarily their first choice.
Which is not to say that Go can't do well in tooling. Only that Go was not necessarily their first choice.