Why even hint at the idea that you may one day shut down and remove access to purchased content? Surely there are ways to build hype without eroding trust in your brand and angering your audience.
Since the games are DRM free, you never have to worry about the publisher, or anyone else, pulling servers offline and making the games unplayable.
GOG can go out of business the day after you purchase and you still have the games you already bought and downloaded.
They're not a game backup service. They're a game store. Once you've bought and downloaded your games, you can make your own backups; you don't rely on them to keep anything available forever.
I personally own a few games on GOG but currently don't have local copies of any. When I saw the notice on their website and assumed they were gone I briefly thought I would never be able to get a legimate copy of the games I bought. One could argue that it's my own fault for not backing them up myself, but still...