paladin181: I don't know why he is not explaining this well. It would guarantee parity because
they would be the same files. The installers for the game would use the exact same files, whether you choose to have Galaxy installed or not. If you've installed Galaxy, it would download and install the game files from the exact same source as people downloading through the website. It's one installer, one set of files. Period. Galaxy isn't downloading a different set of files from a different source than the game page downloads through the website.
Essentially exactly what you stated, except the installer would have an option to install galaxy if you chose. That's is. That's what he meant by stub.
I also suspected that might be what he wanted to say...
...but it still doesn't explain why there would have to be the option to install the Galaxy client among those game files (installer, whatever you call it). What does it have to do with anything? Why would it be needed for this to work? That is the part that didn't make any sense.
EDIT: Although, after reading the OP's last message, it actually seems he is suggesting the opposite that i was: he is apparently suggesting that the Galaxy client would not download and install the games the way it does currently, but instead it would download those same offline installers that you can currently download with the web browser, and the Galaxy would apparently install the game by running that offline installer.
I was suggesting the opposite, that the "installer" that non-Galaxy users would download from the web page, is merely the exact same files that Galaxy downloads nowadays, and on top of that some mechanism to install dependencies and setting registry entries etc. (it could be an install script the user has to run manually, or it is run automatically the first time the user runs the game... and then there would have to be some uninstall script too to get rid of the game (registry entries etc.) afterwards.
I see many drawbacks with his (apparent) suggestion as then the Galaxy would not be able to download mere changed delta files when auto-updating installed games (but instead it would have to re-download an updated game installer all over again and install it over the old installation, or at best a separate update installer, if available).
Also the downloads would be bigger with Galaxy, like if you compare how CP2077 offline installers are over 100GB compressed, while the installation (that Galaxy currently also downloads) is 69GB or so,
uncompressed.
And a third thing, the current offline installers are more wasteful in that they apparently first uncompress the installer files to the system directory, and after that install the game from those temporary files.
And also in this case, I have no idea why those installers that Galaxy would download too, would have to have the optional Galaxy client installation query/stub/whatever. Again, what does it have to do with anything? What would be its purpose and benefit?