Well, I consume more open source software that I will ever produce, so I am in a dept to the community. If it means working a bit more to make my contribution useful to others and fit it into the bigger whole, I will gladly do so.

Valve contributed to Linux before, so the fact that they don’t have any direct upstreaming plans right now indicates that something is causing friction.

I would avoid reading too much into it. They and their developers are still contributing on other stuff. Also when working together, there will always be some friction, in any collaborative project ever.