The better question is: Can we trust Microsoft with .Net Open Source?

Open source that is somewhat close to a core of a what a company is doing is always a fine line to walk. See: ElasticSearch, MongoDB, MySQL, Databricks' Deltalake, Oracle's GraalVM, et al.

This development is (generally) very unfortunately, and for those using .Net very annoying.

But let's not forget, overall Open Source is great, and it's great that Microsoft has (finally) turned in that direction. There are a lot of other, successful Microsoft Open Source projects.