QuilotoaThe artificial gravity generators never seem to get destroyed in space battles.
Gravity is on a separate subsystem & power supply, because without gravity people couldn’t reasonably move and fix the rest of the ship, so even when compared to general life support, it’s the most critical function and the most isolated.
And production cost.
In David Weber’s Honorverse, artificial gravity is based on the drive system, and was routinely considered both in ship design and battle outcomes.