Why is that less realistic than saying 'rewrite in rust, make sure there are no memory leaks'?
My point, which I should have been clearer with, is that we aren't at a state where you can just one shot a rewrite of a complex application into another language and expect some sort of free savings. Once we are at that state, and it's good enough to pull it off, why wouldn't the AI be able to pull it off in C as well?
You don't have to trust the AI to do it with Rust, you just have to ensure certain conventions are followed and you can formally prove you're 'safe' from certain classes of issue, no AI magic dice-roll.
A lot of people are very excited by the idea that now language capabilities (and almost every other technical nuance) somehow don't matter but much like gravity they will continue to assert themselves whether you believe in them or not.
So far humans have proven unable to write large apps in C without those issues, given their work is the training basis for LLMs this creates two problems, one being that they don't 'know' what a safe app looks like either and any humans reviewing the outputted code will be unable to validate that either.
Documentation and testing used to be mildly important, you better have them, but the quality of the tests didn't matter as much, since you have to get the implementation right, no matter how good or bad your tests are.
Now that the work is delegated to an LLM, the test and documentation quality ultimately decides the quality of the product.
Since you as the programmer no longer have to deal with the language's annoyances directly and force the LLM to perform the drudgery for you, you can build a language that makes a trade off between drudgery and quality and receive a software quality upgrade essentially for free.
LLMs are really good at producing tokens faster than developers, so make those tokens count.
My point, which I should have been clearer with, is that we aren't at a state where you can just one shot a rewrite of a complex application into another language and expect some sort of free savings. Once we are at that state, and it's good enough to pull it off, why wouldn't the AI be able to pull it off in C as well?