So just because something is trivial doesn't mean that it doesn't require time to implement the rules. You can be entering a bunch of convulted rules into a GUI based system or you can be writing them in code.
I largely actually prefer the code way, believing it's much more flexible, sane and safer. However, the problem is the average person who understands these rules is scared of the code, and the average coder is much more interested in solving a lot of inconsequential problems.
This makes it much harder to pay someone in who's just going to sit down and churn out your CRUD and when folks find these guys, they're either keeping them happy or think they're easily replaceable and will have a fall later on.
I'm doing devops at a big org at the moment. They have several dev teams working on bespoke low-traffic resource managment applications. Most of these have 5 developers, devops, delivery manager, user researcher, designer in addition of going view a technical review process, pen testing, performance review, and functional testing.
Basic math suggests that's going to come out at about £350,000 per project over 3 months. A million quid later, they've all passed reviews without any of these so called highly technical people realising they're dealing with a common problem and that they're developing 3 of them. Also they're all shit because they're done by MEAN stack tech hipsters who haven't quite realise they're leaking important data.