D has been fully unproprietary since 2017. https://forum.dlang.org/post/oc8acc$1ei9$1@digitalmars.com

But that's only the reference compiler, DMD. The other two compilers were fully open source (including gcc, which includes D) before that.

Fully disagree on your position that having all possibilities with one language is bad. When you have a nice language, it's nice to write with it for all things.