You could say the same thing about Windows: Windows just isn’t an option yet.... maybe in 5 years when WSL is performant and MSFT has open-sourced enough to not be a threat to more cautious companies.
No, I don't think you can say that. The point is that I have clients that use linux, clients that use windows, and clients that use both windows and linux which need to talk to each other. I need a solution that can factor out the operating system into a module and build packages that will work for both the quants and the servers. I don't get to tell my clients what operating systems to use. I must provide solutions that work on whatever they're running.
Nix has facilities for creating Docker and Singularity containers from a nix expression, which lets you package up arbitrary environments. Does that satisfy your use-case?
