[meatysnapper]

Yes. Any proprietary system will require you to document/educate the users, and you will not have the benefit of an online community to get help from, or bug fixes, or security analyses. There are very few problems where rolling your own solution is the right solution. Maybe if you are Google and your database isn't big enough or something.

If you have great people building the software, or at least competent ones, and you have competent users, you might succeed, maybe. But that's assuming you have a maintenance plan and a roadmap, which most software companies do not. Maintain software? YOLO! What happens when you have a bunch of morons using and maintaining the software?

In short, computer science in industry is largely practiced as shamanism by people who cannot engineer their way out of a crackerjack box.