Because I'm beginning to think the devs/publishers have written off GOG.

Yes, it is. Slower than Steam, but faster than android or consoles.

You're able, by the way, to check when any given game was last updated on GOG by looking at the games details on https://www.gogdb.org/. I don't know how to tell the exact current version number of a game without buying, but you're able to see the date it last updated.