I don't think it will be like that, for two reasons.
One, coming up with a correct description of a program is what computer programming actually is. Implementation is something we're always looking to do faster, so we can describe more behaviors to the computer.
Two, we're nowhere near the scale of software production which would clear market demand. If everyone who writes code for a living woke up and was ten times as productive, there would be more churn than usual while the talent finds its level, but the result would be ten times as much code per year, not five times and 50% unemployment.
Today I wrote a little bit of code to generate a prefix trie and write it out in a particular format, with some extra attention to getting the formatting 'nice'.
This took me about three hours.
It won't be long before something in the nature of Copilot could have gotten this down to, maybe, a half hour for results of the same (minimal, acceptable) quality.
Wonderful! Can't wait, I'll be six times as productive at this kind of task.
This might make it hard, on the margin, for some of the more junior and glue-oriented developers to find work, but I think the main result will be more software gets written, the same way using a structured programming language got people further in a day than writing in assembler did.