In an interview with CNET, director Aya Kyogoku was asked about the future of New Horizons, and what's coming down the pipeline. Kyogoku states that there's lots of stuff in the works, and they're looking to keep players engaged for years to come.
We want to make sure that in two years or three years down the road, players will still continue to find new surprises in the game. So we hope to create an update that you can do that with.
It's worth reading the whole article, where they also talk about cloud saves, Tom Nook being nicer, and more!