There's this misconception that Steam is DRM. Steam is just a delivery system, but Valve supplies tool to implement DRM if developers and publishers want to make use of them. Steam games do not require Steam to run unless it is configured so by the game's manager. Skyrim on launch did not require Steam to run, but Bethesda patched it later. Many older games do not bother with Steam dependency, such as Commandos 2. Move the game folder around, copy it to another PC, launch it from the exe with Steam closed (and Steam will not start up).
It makes no sense to say "We will offer a Steam versio