I am mostly thinking about Pokémon. They’ve got this rich new Pokémon Home system to transfer between generations, but that’s reliant on having functioning older hardware. Now, there’s a massive pool of functional 3DS systems out there, so it’s not a pressing issue, but eventually, some poor Ash Greninja will be trapped on a 3DS cartridge. (I suppose the answer is: port all the Pokémon games, profit, swim in giant Scrooge McDuck moneybin of coins.)