The design of typefaces aren’t copyrighted in the U.S. The only thing that is protected is the software: TTFs, OTFs, etc. [1] That’s why so many clones of popular fonts (and old metal type) exist.
These days the value in a font isn’t in the letterforms, it’s in the kerning, ligatures, variability, etc. which all flows from the software. It’s also where a significant amount of the labor in creating a typeface comes from. And it’s the thing that sets apart professional-quality fonts from many (but not all!) free ones.
If AI can write new font software by cloning bitmaps of letterforms _and_ get the kerning, ligatures, variability, etc. right… it’ll change the type foundry industry in a big way.