I don't think there's a ceiling to LLM capability. I do think that many software dev tasks are just far below that ceiling, and the gains to most dev work won't be that large from now on.

Where the new generation of LLMs (Fable, Sol) shines is tasks that are much harder than typical soft eng, yet that still have a verifiable answer, think mathematical proofs or exploits. I think there's still a good amount of low-hanging fruit in those (and similar) areas.

The next frontier after that is tasks that don't have automatically-verifiable answers, and may not even have correct and incorrect ones in the strictest sense of the word.

Reasonable lawyers might disagree on the question of "which trial strategy do I use given the following set of facts." There are answers that are clearly wrong, but being able to choose between many plausibly-correct ones requires many years of lawyering and seeing many trials play out. I do suspect that most lawyers are far below the ceiling that a hypothetical immortal lawyer that has practiced for an infinite amount of time would have achieved.