I think Github already offers BYOK (bring your own key). I think the problem is that you are still expected to pay for all the premium subs, the key only allows you to go above the rate/monthly limits.

I think Jetbrains does it better with a full BYOM for models, including ollama. And I think if you go for ollama, you only need to pay for the IDE license, not for the AI add-on but don't quote me on that.