This is my guess too. Programming languages currently have to make tradeoffs around cognitive load and the ability to fully reason about effects of statements.

This is my guess too. Programming languages currently have to make tradeoffs around cognitive load and the ability to fully reason about effects of statements. An AI assistant with stronger reasoning ability might allow the creation of more powerful languages than we're capable of using by ourselves. (If this sounds dangerous to you -- to use a technology that humans aren't smart enough to understand ourselves -- I guess I'd agree.)