I'm not sure.

The cost of replacement-level software drops a lot with agentic coding. And maintenance tasks are similarly much smaller time syncs. When you combine that with the long-standing benefits of inhouse software (customizable to your exact problem, tweakable, often cleaner code because the feature-set can be a lot smaller), I think a lot of previously obvious dependencies become viable to write in house.

It's going to vary a lot by the dependency and scope - obvious owning your own react is a lot different than owning your own leftpad, but to me it feels like there's no way that agentic coding doesn't shift the calculus somewhat. Particularly when agentic coding make a lot of nice-to-have mini-features trivial to add so the developer experience gap between a maintained library and a homegrown solution is smaller than it used to be.