In a month from now Splatoon 1 will basically be unplayable on an original unhacked Wii U. Sure you can do the single player story mode, but the main multiplayer mode is going to be gone by then unless you use Pretendo. I think the Switch is actually in a better situation because it has paid online so as long as enough people pay for online for Nintendo to keep up the budget for server maintenance it could potentially last decades while Nintendo has an incentive to cut online for their older platforms that they are basically paying to keep up for free.