Of course, but again the issue is the number of people. Software development, as it currently is, has huge barriers to entry. Working in code is something that many people simply cannot do, and of those that can - a huge chunk will find it intolerable as an occupation. 'Prompt engineering' will have far smaller barriers to entry which will, even all other things being equal, significantly increase the labor pool.
My wife knows how to prompt chatgpt, but she wouldn't be able to create an app just by putting together what the llm throws at her. Same could be said about my junior engineer colleague; he knows way more than my wife, sure, but he doesn't know what he doesn't know, and it would take a lot of resources and effort for him to put together a distributed system just by following what an llm throws at him.
So, I see the pool of potential prompters just as the pool of potential software engineers: some are good, some are bad, there will be scarcity of the good ones (as in any other profession), and so wages don't necessarily have to go down.