Programming is independent from language
(A) COBOL supports many vital processes
So don't try to squish it through a mincing machine and trust it.
(B) The bad news is it's been working for a little long.
Longevity is not a sign of weakness, a lack of headcount knowledgeable in COBOL is the problem.
(C) "If you can find a COBOL programmer, they are expensive..." + there are billions of lines of COBOL code...
Sounds like a reason for learning COBOL for some, it's a supply/demand no-brainer.
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Programming consists of logic with one of three choices in program flow: sequence; condition and iteration. All programming logic follows this, and all languages accommodate it[1]. If you're a programmer, you can code your program in any language you know[2] .
Converting code autonomously is essentially starting from scratch, autonomous reverse engineering, without the human taking hands-on until testing - that won't leave any bugs. (Hugely impacts A)
If (A) is important, you really don't want to risk this approach, it creates a mind fuck.
(B) appears to be/is the case because of FOTM, it's chic to code in Python/Rust/Java... or whatever. It doesn't matter[2].
If you combine (A), (B) and (C) it's clear that's what is "needed" is for more COBOL coders, not a farcical "AI" fix. (A) because the $Corps should stop fucking about and help themselves by not scrimping, and (C) benefits the programmer. They combine to (B).
[1] If that's not the case, it's beyond the scope of the significant context.
[2] If it's the right language for the job.