Survival of the fittest. Either make your faction fun and appealing to players: both to join and to interact with in space.... or suffer inactivity.
The highest form of disrespect and disapproval is to choose NOT to interact with a faction. If a faction is blaming no one wanting to interact with them as a reason for inactivity then the faction need only blame themselves and their behavior.
That said there are too many systems and too many factions. Start getting rid of buffer/ garbage systems and redundant lawful and unlawful factions. Do that and space will seem less empty.
