It looks like they've downscaled this from being a broad feature to only available for Home edition. Comparing the Windows 10 and 11 versions of this page, Windows 10 S Mode was available for Home, Pro, Enterprise and Education, but the latter three are no longer available.

It seemed to have been touted as an education-oriented feature when it was first released, but presumably that didn't resonate with the market.

"Windows 10 in S mode is built to give schools the familiar, robust, and productive experiences you count on from Windows in an experience that's been streamlined for security and performance in the classroom." (From https://docs.microsoft.com/en-us/education/windows/test-wind...)