My entrepreneurial motto is that you may or may not be able to sell an application, maybe nobody needs it, but eg. furniture will always be sold. It only depends on the price, the time and the quantity. One of the possibilities that I see nowadays is to create a service that makes posters using Midjourney (it’s so cool that we can upscale those images!) and sell them. It may be surprising, but sometimes posters are pretty expensive, but printing them in some local printer place is pretty cheap.