The very nature of AI is that anyone can make their own model with enough training. There are already open versions of Copilot available, such as Fauxpilot, or GPT Neo for GPT-3, so I never understand the "only rich and powerful will have AI." I mean, sure, some will, but just like programming, the effort will eventually be distributed to open source versions.
As an OSS contributor you can nicely ask people building some OSS equivalent of Copilot to not use your work as training data, and they would comply because this is culture. Good luck doing the same with a megacorp
