I wish I could compel my team to write more open source code at work. Giving back to the community while shrinking our code base and growing their architecture

I wish I could compel my team to write more open source code at work. Giving back to the community while shrinking our code base and growing their architecture skills - how good is that!? Sadly it seems like most people want to talk about open source but not many are actually keen to put up a pull request in public. I suspect there’s an idea of open source being fun, experimental, not-useful code that exists in isolation. That’s not really the kind of open source I want to fund, but I’d love to see bug fixes and performance improvements upstreamed to the frameworks and tools we rely on. Anyone figured this out?