There are DLLs that remove any check of Steam running. Just keep a copy of one and use that on other games.
Regarding the download, it's the same issue with physical media. If I don't have the DVD, how can I acquire the game?
Oh there are Dlls? And as a non-technical consumer I just know this do I? I know how to dig deep into my file system and copy+paste a dll file into software I can’t/don’t understand? How do I download and install a copy without Steam?
This is just piracy. This is no different than downloading a crack. This is not some great service offered by Valve/Steam, it's just a cracked binary.