Keep in mind that TOS sets are probably the cheapest to make compared to the much more expensive sets of the modern Trek shows. They can get away with being cheesy if it is TOS.
I would imagine the TNG bridge would be cheaper to reproduce. You only have to use four monitors for the back wall and every other control interface is simply painted plexiglass.
Every station that rings the upper level of the TOS bridge has to have working monitors to recreate the blinkies.