I'm pretty sure they are, otherwise why would it takes days or weeks for them to update?

There is at least *something* manual involved, at least some time ago it was.
I remember that after the release of Pathfinder: Kingmaker, that the developers released patches on the weekend, and those where immediately available in Galaxy. Apparently, developers have a direct interface to Galaxy, similar to how Steam handles game updates.
The patches and updated offline installers then came on monday.

I know a good number of us can be down on GOG at times, certainly I am a bit now and then, and it's not like they don't deserve it at times, but compared to some other stores they still look pretty good much of the time.

Have a read of the following thread of mine, to see some of what I mean.

https://www.gog.com/forum/general/the_guild_2_venice_sighting/page1

Not necessarily, they quit supporting WinXP so they could do the same for Linux.

For what it's worth, I think that removal of offline installers is highly unlikely in the forseeable future. They are GOG's Unique Selling Point and without them, it would have nothing to distinguish itself (in a positive sense) from Steam, GamersGate and other online stores.

The main reason why Galaxy is being pushed down everyone's throat is almost certainly due to its multiplayer aspect - this can only work if lots of people use it, increasing the likelihood of finding partners/opponents for any given game at any time.

The more likely scenario is the one discussed here of offline installers not being updated promptly. It's easily fixable by GOG allowing developers to create their own offline installers (and this really should apply to "In Dev" games where frequent updates and less-than-perfect gameplay is part of the experience) and probably the best way to tackle this is to raise support tickets on any out-of-date installers.