Yeah, the cases you mentioned indeed happen quite often and I agree that it is best the backup the installers. Also, I should note that in my case I haven't truly lost the game as it came with a Steam key, which I have activated, so I still have access to it. It is just that from my previous experience with the two digital game stores I am mainly using, when a game is removed from the store, it still remains in the library of whoever have bought it up to the moment of its removal. This is why I wanted to confirm if my case is expected, or I have encountered some error with my account data.