Sorry for my ranting - thank you for your quick responses.
I'm sure part of the reason for the gouging of the female end is that people forget to push the knob in before turning it. They'll twist it initially, get no gas, THEN push in and twist, but we've had this issue since we bought the grill. Without the knob, I can push the valve in and twist it pretty easily, so I think it's user error. And I can now understand the reasoning behind having the female end of these knobs be more of a "breakaway" style for safety reasons, but it's a royal pain in the ass when they're stripped. We've had to replace the knobs every season, which is just dumb.
We don't have that many people operating the grill in a given season, so I'll look into lubing up the valves and maybe etching a reminder on the grill panel to "PUSH, THEN turn". Thanks!