Just did a GOG survey that focused on the idea of a paid membership option on GOG. Seems they're determining what people would be willing to pay extra for. Some of the options were
- a tool for backing up offline installers
- ability to install previous versions of a game
- extra insight into the preservation work they're doing.
- voting rights on games to bring into the preservation program.
And others that I can't remember.
I'm fairly sure the update cadence is set by the game dev/publisher, not GoG.
... and Steam is more important to them than GOG
They might have to grease some wheels somehow then. Some kind of incentive structure to make sure they do it.