Actually not like ET at all. 40 years later you can still play ET carts you find in some dust heap.
More like Warhawk (RIP Incognito), MAG (RIP Zipper Interactive), etc. Not the first time owning a disc didn't mean you could play forever. Won't be the last. I wonder if Babylon's Fall has enough fans for people to try to resurrect it on their own like with Warhawk?