Well I certainly was oversimplifying things as I am not much of a developer of any kind - I am speaking from my own observations and speculations. Probably should have indicated that earlier as to not to confuse anyone, pardon, guys!
Paraphrasing what I said in my previous first. I know nothing, guys, I'm just a guy with a keyboard and some enthusiasm for computers and programming.
I imagine some games being installed in a manner that gets some archives onto your storage device and proceeds to extract them. That possibly includes arranging the files on the storage device in a suitable and sensible manner, as in, if the installer works with HDD, it makes sense that it tries to put the entire game at the end of the HDD to avoid any possible fragmentation. For instance, sometimes when I download a big game via Steam, it keeps telling me it is working on some files after the indicated GBs have already been download; again, to me seems as if it is either arranging the files in the best order possible, deleting the installation files, or both.
I am not saying that you, as the end user, have much of a control over any archives, installation applications or files that modern launchers probably use to get you get the game. If there are any archives or something similar, it is most likely automated as to get everything done as neatly as possible (hopefully) and then get the extra stuff out of the user's system. Think about moving to a new place - the boxes we use to store out stuff are either kept in one special space (to occupy as little space as possible or, at least, not get in the way) or thrown away entirely (at least some of them).
ACCORDING TO GOOGLE (or, more specifically, Quora):
Steam, for instance, merely reserves some space on your storage device before it installs the game. It creates all the files, names them and only after that fills them up with some data, basically installing and downloading games simultaneously. The final step here is installing dependencies like DirectX, Microsoft.NET, etc.
TL;DR: The Internet says I'm wrong and, at least in case with Steam, digital distribution platforms don't bother with getting some archives and other crap onto your storage devices - the game is installed and downloaded onto your system, into its own files. The application seems to simply pre-allocate some space for whatever reason (possibly file arrangement or making sure there's enough space for various dependencies).