I don’t think that response makes sense. The classic instrumental convergence arguments are about a single agent; OP is asking why distinct AIs would coordinate with one another.
I think the AIs may well have goals that conflict with one another, just as humans’ goals do, but it’s plausible that they would form a coalition and work against humans’ interests because they expect a shared benefit, as humans sometimes do.
What specific rhyme-related tasks are you saying ChatGPT can’t do? I tried it on some unusual words and it got a bunch of things right, made a few weird mistakes, but didn’t give me the impression that it was totally unable to rhyme unusual words.