Yes but it's mind-boggling how complex you can get quite a straightforward system by just piling new requirement changes on top of old without maintaining prope

Yes but it's mind-boggling how complex you can get quite a straightforward system by just piling new requirement changes on top of old without maintaining proper data-model in application, even if database is fine-ish, this results in a monster that slows down the system and the development speed. So in principle, a lot of people can do it but only some do it while not making things more difficult for the next person.