FWIW I also think general protocols on long lived platforms and IPFS are great.
BUT, I really don't think the blockchain has a role to play solving any of the issues you laid out. The reason the game you mentioned was able to continued to be played was because Apple was providing the network. The minimum ETH write fee is almost always at least $1 and frequently cost $3.50. Would people still be interested in playing the game if each write cost that much? Same goes for your archiving plans. IPFS is great but it's not a guarantee that that data will be seeded forever. For that you'd need to write it to one of the chains you're confident will survive. ETH data costs somewhere in the thousands of dollars per MB range? I'm not sure it's a real solution to that. I'm not dismissing the issues of very long term code and data longevity. They are real issues but in my opinion still quite unsolved.