TheJoe: So debs, rmps, makepkgs and tar gzs for everyone?
No. It won't happen because Linux is stupidly chaotic and all over the damn place. I use Arch and I look at how easy it would be for GOG to create AUR-like scripts, but it won't happen because they'd have to please the Ubuntards*, too.
It's why no games company can reliably support Linux. The disparity between package managers is too extreme. If you want pretty menus, you have to deal with all the different Desktop Environments and their way of handling things, too.
And, see attachment, it's not difficult to build nice menus yourself. For GOG games, you can open .ico files in Eye of GNOME and Save As PNG for icons.
Maybe some day, but not while GOG is tiny and doesn't want to over complicate things.
* People who use Ubuntu simply because "it's not Windows". Generally 12 years old. I'm an ex-Ubuntard.
Packages? What for? Surely packages would be nice, but all you need is a whatever self extracting installer (there are plenty of those ready to use) that automatically creates menu items - that's all. Well... maybe to make everything just right a 32bit & 64bit version of dosbox + (optionally) needed libs and (optionally) a shell script that sets LD_LIBRARY_PATH to bundled libraries. I guess 15 minutes to make all that would be just enough.
@Trilarion yes, Linux can unzip and pretty much un-everything you can think of and many more ;-).