I'm not sure what I agree with, but I think it's interesting to think about.
My off the top of my head guess is it makes it easier to make new programming languages and have them be usable by people, but it reduces the value of new programming languages. So both things happen. We end up with more new programming languages because they're easier to make and use, but more of the usage concentrates on the existing languages and the ones that ChatGPT is best at. So both a bigger long tail, but more concentrated 'big winners'