GitHub should have insight on new repositories and repositories that are gaining files like CLAUDE.md and AGENTS.md that kind of tip off the use of AI coding.
My guess is there's a super long tail of projects people are releasing as open source that were vibe coded to solve some simple problem. Most will likely fall into abandonment or never reach any amount of viability.
On the other hand the cost of starting a project to solve an interesting problem has never been lower. It's never been easier to take a swing at building something cool that people might like. This should expose new opportunities that haven't been attempted yet.
My intuition says it's not all bad. It's like selling hammers to people who aren't licensed construction workers. Yeah, some stuff will get built that should not be built.