So? Just because your code is not open source does not mean you're not allowed to use it.
They might not care about the company they are applying to opensourcing their code. Plus you have to try really hard nowadays to not use any open source code at all
If you go through your dev career thinking only people who write and use open source code are brilliant you'll miss out on the opportunity to learn from some of the industry's best developers. There are loads of people working on entirely closed source projects who are very, very good engineers.
>If you go through your dev career thinking only people who write and use open source code are brilliant
I didn't said that. I have just pointed that even close source developers are using open source when working daily on their closed source projects. So saying they don't care about something they use daily is ....wrong. Also I didn't said anything about their level of brilliance :)
Using open source in many enterprises is just a way to save costs, many times at expense of productivity as there are closed source options that are actually better, but not all companies are willing to shell out the cash.
Contributing back, or even announcing to the world that such packages are used is not even a thing.
I didn't said that. I have just pointed that even close source developers are using open source when working daily on their closed source projects.
When I said "entirely closed source projects" I meant that literally - some projects have no open source elements. They're written in closed source languages that you have to pay for, with closed source libraries and frameworks that you also have to pay for. They tend to be things like control systems in small industries, unusual embedded systems, and so on.
The software industry is big and hard to make general statements about. "All developers will use open source code" is not true.
The obvious irony here is those "brilliant" engineers will use open source code even though they don't care for it.