I think you misunderstood me, I never claimed that excessive file size can’t be a problem for the end user. I was saying that in regards to cloud save, large file sizes shouldn’t be a problem for the end user. It’s a problem GOG should take up with the developers they allow selling on their storefront with GOG’s advertised feature set.
I’d like to challenge you on that edit of yours though. On an SSD the time it takes to load a save file into memory is negligible, and in almost all cases less than the game assets the game loads up when you start a game. The complexity of the game world is the dominant factor.