Comment by creamyhorror

This was previously phrased in startup advice as "start with a single vertical and generalize afterwards", "don't try to boil the ocean", etc. A lot of less-experienced entrepreneurs start with wanting to conquer all markets with their new paradigm, but the truth is you first need to capture specific segments/verticals or you'll be spread too thin.

Similarly, with a software solution, you need to make it integrate into an existing stack used in the market, or else build the layers to make it something that can fit neatly into a business's processes. E.g. if there's already an established market for engines or frameworks, then a business can use your conforming engine almost plug-and-play. Otherwise you have to build the app and UI layers on top to make it end-user-facing.

Once you've achieved some success in a vertical or layer (e.g. appointment bookings for salons), you can abstract the core solution/framework and start applying it to other verticals or build adapter layers to start attacking other layers (e.g. appointment bookings for everything).