Having giant loot pinyatas in space sounds like a great reason to go to war! The chance for Titans etc to drop, fantastic! Even if the structures dropped only 10% (50% of 50% sounds like more fun though) that’s still a massive payoff for a successful seige.
@Bronson_Hughes’s idea of modifying the drop rate is fine, though I think that 100% safety should not be achievable, something even if it’s not much, should always drop.
Trying to protect your loot, by ferrying it to a nondestructable NPC station, in NPC sov/low/high sec where ancibel jumpgates can’t be anchored creates another oportunity for interdiction, there will be a lot of material moving, JFs, carriers etc with cynos are safer but plenty of people will likely not use those everytime. This did happen when stations were indestructible and only ownership of the station and the ability to access the items changed, firesales and panic hauling, those assests were 100% safe from destruction, they’d just be locked away.