They bought x-number of Proton monitors for TFF, and it wasn't anywhere near enough to fill all the screens for the new bridge they wound up building, hence all the polarmotion gags and the okudagrams to fill out the non-monitors screens. Though why the monitors used from TWOK onward were gone, or where they went, who knows?
Were the TWOK screens actually full color? I recall the displays being monochrome-only in TWOK/TSFS, but I don't know if that's because of the animation used to drive them or if that was all the monitors could do.
Anyways, seeing as how the TFF displays were full-color, they probably wouldn't have wanted to mix-and-match. Assuming, of course, that any of the TWOK displays survived both the bridge damage in TSFS and the years in storage.