They do new stuff all the time. Ask your AI to draw a gerbil riding a unicycle around Pluto and you'd get an image that hasn't been there before. If by genuinely new you mean without any help from past culture, do humans do that?
For significant pushing the boundaries of knowledge stuff you maybe need different algorithms like AlphaGo move 37 or Alpha Fold protein folding. Though again how often do humans do that?
Humans do that by inventing algorithms like AlphaGo :)
In a more serious note, I think the person you are responding to meant "new" more in line with "novel".
Take a microfluidic chip, for example. Current AI systems can create new flow cell geometry, but cannot come up with the idea for a microfluidic flow cell itself.
Yes, but also no. If I prompt a graphics artist, "draw me a picture, any style, of a calendar with this day circled in red", you do not have to tell them what a calendar looks like, what the days of the week are, or how many there are, or that days in a month increment sequentially.
Also, you probably don't need to tell an artist "don't violate other people's copyrights" while you're at it, though that's perhaps somewhat more debatable than "does the artist know that the day after Thursday is Friday".
This applies equally to all disciplines: AI generated code regularly contains wtfisms that a human would not need to be guided from, or at the very least (more similar to the copyright problems) that experience and knowledge would drive them away from — and permit me to entrust, particularly more experienced — humans with a vague outline of the idea, and trust that the details will get filled in sensibly. "Filling in details sensibly" is where AI hallucinates the hardest.
For significant pushing the boundaries of knowledge stuff you maybe need different algorithms like AlphaGo move 37 or Alpha Fold protein folding. Though again how often do humans do that?