Proprietary software for scientists and engineers all tends to have the same problem; their users aren't (primarily) programmers, so they'll only write their own tools if it doesn't take too long or there's nothing close to what they need available, but they will figure out a way to solve their problems with whatever they can find. It's really, really hard to write software so shitty those guys won't be able to make it work, and as long as they can make it work they'll be content. That makes it hard to make a commercial case for doing any better than just good enough.
Yeah, buncha my coworkers have built up personal libraries that they are loath to share with anyone. Not that it would do you much good anyway... doesn't matter how well it's commented, you're going to end up trudging through the mud to figure out what's going on, and you might as well have just written your own program to begin with. Most ridiculous piece of software in my industry has to be SIMION, for that exact reason. C'mon, even the website is straight out of the 90's.That makes it hard to make a commercial case for doing any better than just good enough.