Prediction: open source will stop.
Sure, people did it for the fun and the credits, but the fun quickly goes out of it when the credits go to the IP laundromat and the fun is had by the people ripping off your code. Why would anybody contribute their works for free in an environment like that?
Many did it for liberty - a philosophical position on freedom in software. They're supercharged with AI.
I believe the exact opposite. We will see open source contributions skyrocket now. There are a ton of people who want to help and share their work, but technical ability was a major filter. If the barrier to entry is now lowered, expect to see many more people sharing stuff.