Well, in the EVE CCP refused to develop, some structures would have been an affordable luxury worth grinding/PLEXing for…
Structures provide a competitive advantage, thus that advantage requires a counter to be balanced. Paying a “anti-wardec” fee or just risking them being destroyed are options, but if a “anti-wardec fee” was paid, that could lead to structure overcrowding. Removing inactive structures should be a NPC mechanic, just make players pay for the removal (“storing” them) and respawning if they come back.