Yes, it will kill open source—at least as we know it.

I’m convinced that GitHub and GitLab will eventually stop offering their services for free if the flood of low-quality, "vibe-coded" projects—complete with lengthy but shallow documentation—continues to grow at the current rate.

The trend of rewriting existing programs ("vibe-coding" a rewrite of $PROG in Rust, for example) threatens to undermine important, battle-tested projects like SQLite. As I described in this comment: https://news.ycombinator.com/item?id=46821246.

I’m quite sure developers will increasingly close-source their work and black-box everything they possibly can. After all, source code that cannot be seen cannot be so easily "rewritten" by vibe-coders.