My first programming "job" was a sort of summer internship when I was 14 for a family owned company called Signature Systems (signature.net). They are still in business. Their product is an operating system called Comet, that if I'm not mistaken was originally a compatibility play bringing software from the previous era of 16 bit microcomputers onto DOS PCs, and then later into Windows. I may be misremembering some of the details but I think at one point a Comet system ran ticket sales at Madison Square Gardens. My summer project was to build a demo using their new support for Windows GUI elements. The last time I spoke with the owners, they told me that they still had customers, including in the textiles industry where loom patterns had been coded in Basic. I often think about it as an example of a legacy system, and smile at the idea of someone thinking they need to rewrite their plaid weave in TypeScript or Rust.

Separately, I have spent the last three years building a web app that replaced a heap of automation scripts for a ~50 person business. These were much more modern than what the OP describes but it had some of the same qualities. The scripts mostly generated google sheets and emails. The replacement is a python web app using SQLite. Moving the company data into a proper database has been a very significant step for them. In some ways, the project feels a lot like custom business software that got built in the 90s.