A lot. (of steppers with the same footprint are available on the market). The footprint is NEMA 23.
Do you think they should?
Further Reading
Upgrading stepper motor for 80mm Spindle
What I Learned While Upgrading To 2.2kw Water-Cooled Spindle #18
What I Learned While Upgrading To 2.2kw Water-Cooled Spindle #24
Onefinity X-50 stock stepper: 23HS30-2804S
Onefinity X-35, Y and Z stock steppers: 23HS22-2804S