[tokai]

>Steam explicitly a service where you buy a defined and limited license for permission

Simply not true. There is really no arguments here. You can run most games directly from the game files without steam. In the cases were you can't you would have issues with DRM in all other venues of purchase.

[flohofwoe]

It may look like that from the outside because you can go to the Steam library directory and double click a game executable directly, but this will still start the Steam runtime and do a DRM check. You can run a game in 'offline mode' for up to two weeks before another online DRM check is required though.

[jeltz]

Not necessarily. The DRM part is optional.

[anjbe]

Runtime DRM is sometimes optional with Steam, but install‐time DRM never is.