With LLMs, the benefits seem to have shifted decisively to typed languages.

Typed languages are much easier to iterate within without breaking things.

The problem is that they require more effort to change things, which makes prototyping hard because humans get impatient.

But LLMs have infinite patience.

So the value of types far outweighs their cost when LLMs are the ones programming.

Is TypeScript the schelling point language?

It's ubiquitous and flexible.