Counterpoint: I’ve often wished the proprietary software I use was source-available so that I could fix bugs for myself.
The idea of doing free work for a company does feel weird. But when some bug is really getting on my nerves, being able to fix it and not have to deal with it anymore is a huge benefit!
Or understand what it's doing internally. I used to dislike Oracle User Group presentations because it seemed as if most people were just guessing what the database was doing under the covers. MySQL presentations on the other hand (a) showed code and (b) were often given by the authors.
This; there are a couple 'freeware' style apps I use where the developer sticks a source tarball on a website alongside the download. Having access to that means I can tweak something for a weird scenario, or fix a bug on a new OS release, and if I want, I can send the patch back to the developer.
The idea of doing free work for a company does feel weird. But when some bug is really getting on my nerves, being able to fix it and not have to deal with it anymore is a huge benefit!