Why isn't there a one-command way to copy someone's desktop setup on Windows?

You want to reproduce an entire desktop design, including Nexus and Rainmeter customizations, without rebuilding everything manually. Windows does support repeatable setup, but application installation and application-specific layouts are separate requirements. WinGet Configuration can install packages and apply settings defined through supported configuration resources; it is not an automatic snapshot of every customization on another computer. Ask the creator to provide a reviewed configuration file, required assets, and supported exports for each customization tool. For Windows’ own appearance settings, they can save a theme under Settings, Personalization, Themes, then right-click it and choose Save theme for sharing. After reviewing a trusted configuration and its resources, apply it using winget configure with the file path. The practical equivalent of a dotfiles setup therefore needs a deliberately prepared package. Avoid blindly running a downloaded one-liner; Microsoft explicitly advises checking configuration files and their resources first.