But seriously, what developers do most of their time is maintanace, they spend a day searching for a bug, just to write maybe one line of code to fix it.
If one doubts that all this can be done by an LLM, use a different LLM for each step. Use committees of LLMs that vote on proposals made by other LLMs.
I don't know, I feel like the sky's the limit, especially if they can be made significantly more power efficient. I think that if they never get any better than they are now, and they just get more power efficient, they'll be useful for almost anything.
I strongly suspect that it will. There are whole classes of bugs that occur because some work is boring 'not quite copy paste' work that devs just don't like doing, and don't pay any attention to when they're doing it. Linters and syntax highlighters already catch a ton of those issues before they make it to production, and GPT will make the rest much less likely to happen.
Maintenance is one area where GPT will also shine, because it's 'just' updating some code to do the same thing, so using the existing code as a set of tokens with a prompt like 'update this code to work with v2 of library X' will be extremely effective. It'll be like having something write a codemod for you.
The future is bright. We'll get a lot more productive stuff done, and spend a lot less time on boring grunt work.