Hey yeah so obviously the only other real alternative is Unix. MacOS is on the roadmap, but we decided to start with Windows since the vast majority of enterprise or commercial applications require windows (e.g. ERP, EHR, Claims Processing etc). MacOS meanwhile is often used for more creative tasks (e.g. design, engineering) rather than automation.
On the Linux side, they do have 2/3rds of the market share server-side, but there are fewer agentic usecases there.