If it ever goes bad, well I hope that that’s an impetus for new open source projects to be started — and with improvements over and lessons learned from incumbent technologies, right at the v1 of said projects.
If it goes bad? It’s too late by that point. And how is open source going to compete with billions of investment dollars?
What would the new open source projects do differently from the "old" ones? I don't think you can forbid model training on your code if your project is open source.
If LLMs turn out to be such a force multiplier, the way to fight it is to ensure that there are open source LLMs.