Many, many years ago, I bought some games via the "Stardock service" - Galciv2, I think, Elemental, then it became "Impulse" store, I bought some more games, notably Sword of the Stars, and Divinity 2, and then it was all sold to Gamestop. I did not like Gamestop one bit, but okay, at least I could still download the games.
But this year, after fresh Win 10 reinstall, I wanted to redownload Gamestop client and download Sword of the Stars which I liked a lot, only to find out that the Gamestop website is gone, the client is gone, the whole company is probably out of business, and my "ownership" of said games probably null and void.
It's a very good lesson learned - steam games, or any other "online" provided games can disappear any day, for any reason, and online services taken as granted can be denied for whatever reason. Only what is in your local storage, or on install files like those from GOG without strings attached counts.