I started doing a kind of `small`, hyperfocused niche, ERP around 2004. Is still halfway.

Look for example:

https://news.ycombinator.com/item?id=39371339

ERPs are a beast that eventually incorporates anything and everything you can imagine, and even then, so coupled to a particular kind of business (or just ONE of them) that there is NO way to make a semi-universal solution.