It was technically possible for someone to write a VB compiler and enough of a runtime to integrate VB code with Visual Fred and the rest of the .Net ecosystem. That this apparently never occurred to anyone says interesting things about that development culture, but the big lesson is to not rely on a single source for a language implementation or tooling in general. Go not only has an open-source primary implementation, it has, like, a few thousand righteously angry hackers in its culture who would take Google abandoning it as a personal affront and would work on a replacement Go implementation in a pure example of spite-driven development.