Besides them talking about it several times through various channels? I’m sure you recall the various discussions on how buildings are set up to use instance tech and don’t pull anywhere near the same resources as a crafting station does or something with an inventory, let alone a Thrall with AI logic running through it. Or you could head on over to Admins United and ask all the sever tech people over there what their opinion is.
And also, I think I’ve more then earned my keep. I could spend the next several hours finding you a link where it was discussed, maybe send you several development articles on the subject. But I’m just going to go with “I have no reason to lie to you.”
That’s what the dedicated server app is for. It’s fine though, I get you are absolutely adamant you don’t want to create or join a free private server with the settings that you want. I’ll never understand it, but I otherwise tip my hat as it’s obviously your decision and not mine.
Pippi Thespians are basically like that, but they still require resources. It’s not like making them nothing but decoration means zero cost in performance. I’m VERY skeptical that such a feature officially implemented would go over well. More likely there would be wall-to-wall “Funcom sucks” posts because they are “only” decorative and non-combatant.

