Win 10 version (e.g. DX12) uses 2.2% of Steam users. Its few days since release. All Linux versions together reached whooping 0.89%. Status under 1 percentage is stable for years.
As long as Larians have to be profitable to be able to deliver another masterpies, I dont understand why to bother Linux. I see only one benefit, allow few nerds scream "Look, I am playing on Linux, and compiling nightly at once. Awesome!"