There are certainly split ergo boards with number rows, but I think the reason they’re less popular is that once people try one of these boards they realize they really like the reduced finger movement. Personally, I am using a square numpad on a second layer (as other commentors have explained) and am really starting to like it. Moving all the symbols to another separate layer also drastically reduces use of the numbers for programming, for example.
There are certainly split ergo boards with number rows, but I think the reason they’re less popular is that once people try one of these boards they realize they really like the reduced finger movement. Personally, I am using a square numpad on a second layer (as other commentors have explained) and am really starting to like it. Moving all the symbols to another separate layer also drastically reduces use of the numbers for programming, for example.