It's so weird to me. When I wrote code for pet projects (this was like 10 years ago and I was doing web dev/apps, basically thought you could just do everything in Chrome) I learned there were numerous ways to deliver error messages. Since I was writing code for an app that I needed to use personally, I just pushed any potential error cases to a <div> that only appeared if there was a success (green) or error (red) notification. Obviously had browser checking to make sure it was actually visible. That way everyone knew that what they'd done worked/had saved/whatever or not. The project was basically a database manager, with an interface for regular employees to input dailies. It really wasn't that hard to just put a fail condition on anything that was mission-critical for the person using it. I guess that can get more complex over time, but the concept of delivering a relevant error message doesn't seem like it should be that difficult or expensive.