I noticed that this game is listed only for Windows and Mac but not linux, but 6 and 7 were both DOS games and can be played via DOS box on linux.

Are there downloads for 6 and 7 for linux? Since gold is windows-only, maybe there's a mix of linux support in here?

No. It's easy enough to just set up and use your own dosbox, though. I wrote a generic guide in this thread, and have written more details about how I do it (not recommended) on this page.

Don't expect gog to change this any time soon, either. There are plenty of games with no Windows component at all that gog won't provide a Linux installer for.

Edit: Or, you could contact vv221 and see if a play.it script could be written for it. I don't use them myself, but a lot of people seem to like them.

This is so weird. I know they used to have linux downloads for both of these games. I know it because I'm playing them right now and I must have downloaded them from here. They used to be a zip file with dosbox included.

I messed up one of my dosbox config files and I went to redownload it to see what the original looked like, but they aren't available anymore for wizardry 6, and the windows version is just a self extracing executable and the mac one is just a .dmg file, so I'm not sure how to get at the actual files anymore.

innoextract will extract it if you don't want to use wine. You may have to get a version from the site rather than one your distro provides, though, because gog uses an unreleased more recent beta version of innosetup.

edit: I actually don't use the DOS version of 7, but 6 works with my default dosbox config with only the following changes, which may or may not be necessary:

[dosbox]
machine=svga_s3

[autoexec]
@ECHO OFF
mount C .
c:
cls
wroot.exe
exit

Thanks for the tip, I will definitely be using this in the future!