Admittedly I go out of my way to avoid including closed source components in my work but that's not just an ideological decision. As the parent points out, and especially when you're a developer, there's a massive amount of freedom and power to open source tools. Don't like something? You can tweak it any way you like. You don't have to worry about the IP owner pulling the rug from under you without notice. I want to use that code on my MIPS32 target? I can try to port it, I don't have to beg the vendor to release a version just for me.
If anything in my experience the archetypal "modern web dev" crowd (the one that got into programming through Javascript, basically) is the one that benefits the least from this because often they don't dare to patch their window manager or their shell to customize them. These days C is often considered a weird arcane language, something like the Latin of CS (including in this very forum) so people don't feel empowered to modify these applications. The fact that modern DEs like to treat their users like slow children instead of exposing the tools that could help them become "power users" probably doesn't help.
Then of course for people who don't actually try to read or modify the source of the programs they use "open source" is more of a political statement than anything else. There's no real benefit for them.
I'm making generalities of course, I'm not saying that all web devs fit this description.
I hope this trend will change as newer, more "friendly" languages like Go and Rust make forays in the system programming space. Hopefully that'll motivate the new generation to get over their fear of system programming and start embracing and customizing the tools their use.