because theres a (very) expensive R&D attached to ordering a custom screen. its why many companies on the market use the same panel when making monitors. (e.g for gen 1 woled monitors from LG, LG, Asus, MSI(?) and i think Acer used the same panel.
just "wanting a higher res screen" isnt something thats trivial to order for, especially since the FW13 uses a 3:2 screen , an aspect ratio usually used by tablets