After filming for GEN wrapped, the sets for TNG were either destroyed (like the bridge, ready room, and multiple other sets) or gutted and re-vamped for VOY (the basic framework for the corridors, for instance, may have been used for VOY, but I am not certain of this). The TOS-era movie sets were designed to be taken apart, put into storage, and then pulled out and re-assembled for each film. The TNG sets were not designed this way. So the Enterprise-D bridge, for instance, could not just be disassembled and stowed away for 2 years until it was time to film the next movie. The studio needed that space to build the VOY sets, and since the Enterprise crashed and was destroyed in GEN, they figured they could just build all-new sets for the next movie, anyway.
I think the only significant piece of the Ent-D bridge that was saved was the horseshoe railing, though they ultimately didn't re-use it.