Bingo, there's all different ways to debate and justify the color changes back and forth, both "real world" and "in universe", so let me just throw one more out there and leave it to FF to make the final decision.
One of the main reasons TOS looks as colorful as it does was as much due to lighting design as it was to set design. As you work your way through the series there are always these splashes of color on walls, doors and floors - partly for dramatic reasons but also partly to make it appear that the same room or hallway section of the filming set is supposed to be a different room in the ship.
Since there's no "other" bridge, lighting there was always for effect. When you take that out of the equation, the bridge is limited to the black/grey/beige tones just like in the films. The only real color on the bridge as far as painting was the red accents - railings, helm/nav console, console edges and the turbolift doors. The rest of the "color" came from set lighting and all those little screens.
Even without set and filming lights, there's still functional reasons for the red accents. When you look at anything, the first thing your mind notices is color - that's what helps your brain then define shape, distance, brightness and so on. In a functional setting like the bridge, the red railings remind people that the railings are there. Having them black or gray in a room where everything else is black or gray, they would mentally disappear from your field of view and could lead to accidents.
Likewise, the blue sections surrounding the overhead screens guide your eye and tell your brain where to focus your attention. Even the consoles had different sheens of black - semi-gloss for the overall surface, high gloss for the inserts the buttons were on. When you sit down at your station, that subtle difference in sheen and texture helps your brain track where your hands should be.
If that shot above could just be "powered down", as 005 said, that might be the better way to go.