A few months ago I wrote a custom web app with data visualization that can run on-top of the old Microsoft Retail Management System. It bypasses the application

A few months ago I wrote a custom web app with data visualization that can run on-top of the old Microsoft Retail Management System. It bypasses the application itself and just taps directly into the SQL Server database. As I was writing it I tried to make it pretty general/generic so that there was not too much code that was specific to this particular small retail chain. I wonder how many retail chains will still be using this POS system after end of life? I wonder if that might be the kind of niche thing that could end up being profitable? Or, would it trap me in a barely profitable situation with just enough customers that I feel like I need to keep it going but not enough to really make a comfortable living?