Comment by MattGaiser

I know one like this and the truth is that he doesn’t bother.

He dramatically improves the processes and code which isn’t domain specific and just leaves the rest a mess.

Improve auth? Yes. Improve finance module? Yes. Build better APIs and SQL queries? Yes.

Fix the problems in the actuarial system for funerals? Nope. That’s when you leave and do it all over again.

They contribute to all the parts not specific to the product but common between many products.