I’m no developer, so I can’t argue about design but I see a difference. Photoshop, GIMP, CorelDraw are graphical applications, consequently once the objects are positioned, it is “easy” to split because you don’t need to reformat. Same for the PDF viewers: in the PDF file everything is chewed up to small pieces akin to graphics (it is obvious when you copy and paste “text” without first requesting “text mode”: you get text boxes independent from each other).
In Writer, there is a huge processing to layout the text. Sending subpages to the printer would probably require recomputing the lay out in a strange way (part of lines should be ignored but correctly justified).
If document is sent to the printer driver using the PostScript language (but other languages are possible), this could be solved by sending also a clipping rectangle. This handles smartly the case when you split middle of a character.