An MMO like Final Fantasy XIV, for example, usually always has some big expansion on the horizon, like the upcoming Endwalker, and smaller events, like the Halloween-themed All Saints’ Wake, leading up to them. If this were any other developer besides Nintendo, you could imagine a world where there were actual content seasons in Animal Crossing: New Horizons, where there are free and paid content drops every few months. All of that comes at the cost of more development, sure, but with such a success as New Horizons, which has an audience clearly eager for more, the payoff seems like it would be there.
This set-up could be perfect for the constant addition of furniture, DIY recipes, game modes, cosmetics, and other elements that would allow Animal Crossing's creative community to thrive.