Being a prompt wizard won't pay as well as directly writing code for the AI systems. They're different layers. There won't be more people directly developing software than there are today in the US market, there may be more overall jobs in and around the process however (ie the tech industry will continue to expand to more people in terms of employment; benefits will weaken, median pay will fall).
Most software developers will be prompt wizards, with required degrees that say they know how to be effective prompt wizards. Then there will be a lot of supporting roles, oversight roles.
More jobs in the industry, lower skill levels, less pay.
We simultaneously won't need and won't want the majority of software developers that exist today (the sheer number of them), writing code in the future. That would be a bad outcome.
They're going to end up more valuable as prompt wizards and checkpoint decision makers, because the AI will be drastically better at writing code (in all respects) than they could ever be. And they're going to get paid less because more people will be able to do it, software development will become a lot less intimidating as a field. It'll be more mass market as a field, akin to being a nurse (4.2 million registered nurses in the US).