That may be true, but for many of Microsoft's flagship open source projects, it is very much about the people. For example, TypeScript has been created and maintained by a relatively stable team of highly proficient developers who have become the face of the project and in many ways the driving force behind its success.
It's important that Microsoft backed them, because it provides a stable environment for the developers to keep working on the project and gives confidence to the community that it's a stable language to adopt. But fundamentally it's the people who are important.
In recent years, Microsoft has shown there can be real upside to corporate-driven open source, especially when it has proper buy-in from management and usage throughout the organization (e.g. VSCode is developed in relative lockstep with TypeScript, and both projects benefit from that relationship).
It's important that Microsoft backed them, because it provides a stable environment for the developers to keep working on the project and gives confidence to the community that it's a stable language to adopt. But fundamentally it's the people who are important.
In recent years, Microsoft has shown there can be real upside to corporate-driven open source, especially when it has proper buy-in from management and usage throughout the organization (e.g. VSCode is developed in relative lockstep with TypeScript, and both projects benefit from that relationship).