(20× bigger project / 10× greater productivity) = twice as many people/workers/employees/freelancers needed
That's how it usually works. There are many examples and many proofs of that. Don't get too worried.
Artificial light gets cheaper? There are more lights and more light colours and hues.
Automobiles get more affordable and efficient? There are more automobiles and more "auto-miles" travelled.
Software gets better/easier? Software gets (exponentially) larger and used on a wider scale.
Artists can do their stuff quicker and easier? Higher quality art, more art, less waiting, potentially less back-breaking work.
How about i.e. super high quality long serialized animations in 2160p 120fps, which need only modestly sized teams to finish on time? Win-win!
Or huuge VR worlds with lots of stuff to do and lots of super high quality assets? Wouldn't that be awesome?
Instead of paying $200-300 for a single good digital painting, we could pay $200-300 for 30 great paintings or even a 20-minute long very sophisticated animation! (. ❛ ᴗ ❛.)
Many (not only) mobile games for example, suffer from a very low number of sprite or 3D models animations (between 3 and 8). Or they even feature only static images. In Age of Empires II Definitive Edition there are only a very small numbers of digital sprites (2D representations of high-quality 3D models). Imagine 20 different house (or other building) sprites for 30 different civilisations per "age"!!
U.S. productivity isn't rising quickly at the moment. So called developed nations GDP isn't rising quickly at the moment (anywhere from 0% to 2%).
Btw, think about all the old games remasters and remakes that AI could help make in a very reasonable time for a reasonable cost...
Or imagine much cheaper, much more available healthcare thanks to AI and robots!! Doctors would still work. They just wouldn't be so tired and overworked!