The simulacrum is friendly to its creator, so I don't think that this logic holds up. The simulacrum is NOT under a compulsion
It obeys command and wishes. Being friendly it's something different. It's created to obey commands. It's compelled to do so. It cannot resist. Even if it still has memory and personality of the original creature. You can order a lion to strictly follow a vegetarian diet. It will NOT be happy, but it will do so.
Being friendly it's just that. Being friendly. Not going to harm, going to help if possible.
If your friend asks you to go to war in his place while he stays home comfortably, would you do it?
I create a simulacrum (Sim1). Sim1 is friendly to me and does everything I tell it to. Sim1 creates its own simulacrum (Sim2). Even though Sim2 is not directly loyal to me, it knows that Sim1 is loyal to me.
Sim2 knows that Sim1 is forced to be loyal to you since its the result of a spell that binds its original will (the one that Sim1, Sim2 and creator ALL SHARE) and until Sim1 designates creatures that Sim2 has to be friendly to (read the spell) or, as in the case, a chain of command is established, the only loyality that Sim2 is forced to enact on is to Sim1. No one else.
Therefore it will not hurt me.
And that's why wizards or casters that try this trick are no longer around. Misconceptions on how loyality works.
Sim1 commands Sim2 to obey me
You do not reach this stage. Sim2 on his own casts a spell to free Sim1 of his condition. Chain never established, chaos and death and destruction. Sim2 is under NO COMPULSION, NO FRIENDLINESS, NOTHING towards anyone but to the spellcaster and what it's memory and personality dictate.
BBEG in question: Usually loyality goes to himself OR evil superior power (that Sim2 is absolutely sure could serve better than Original and most likely Sim1, but Sim1 is the spellcaster, so i'm friendly and won't hurt him).
There's a third option you haven't considered and that is that the simulacrums are simply extremely sophisticated machines lacking free will.
I did, just did not go into specifics since it just defeat the original purpose of having indipendent copies of someone going around. A machine lacking any form of free will has to be programmed, which means that no matter how much time you spend on it extremely complex tasks are outside of the scope of the machine itself. It would require sucha complex and intricate programming to even simulate an appareance of life that indipendant action is out of question.
Something like Alexa can be programmed to give me recommendations based on my preferences, without having to worry that it's suddenly going to attempt world domination. It has the appearance of free will but can't draw outside the lines.
That's no free will. Not even appereance thereof. There's also to say that free will ITSELF can be said to be unknown to us since in the end we move and act in reaction to stimuli.
Similarly, I think that a simulacrum can open doors on its own, and yet isn't going to decide to take over the world without input from its creator.
It will open doors on his own if asked to go an retrieve an object from the study. It would probably also close the doors behind itself if such is your preference automatically, since that's part of the memories and personality. Possibly it's going to act with some sort of intelligence if tasked to capture a fort on its own, this does not mean coming up with a PLAN to do so, but apply the "fireball to troll = good" part of the knowledges that it has. It's not going to spontaneously rule on it unless tasked to. It will not learn new ways. It cannot learn. it cannot adapt. Its going to be unfit to rule, since it cannot accomodate to change its perspective. It can only execute. Alexa "learns" from your preferences. A simulacrum cannot.
Either you give it credit to be able to make decisions and then it might backfire, or it cannot make decision and it becomes useless for OP purposes (there was another place where he explained what he wanted to do with a bit more details) of replicating someone else. It will sound fake because it IS fake in the worst way: It cannot learn.
Besides, if creating a second simulacrum is going to always blow up in the creator's face, wouldn't it be more straight-forward to just rule that a simulacrum cannot have its own simulacrum? I'd rather that the base assumptions of the game are clear from the get-go, rather than building a gotcha into the spell.
Considering that the Simulacrum chain is a "gotcha" in itself? Because the Gotcha was not accounted for in development and if it was the wording would have been different. As is it has been left in there intentionally instead of having been errataed so that the DM (and not the players) have the final say on where things will go if someone attempts it. And you are not creating a second simulacrum. You are having a simulacrum create a simulacrum trying to bypass the rule that explicilty states that a creature can only have a simulacrum. So no, i do not feel bad at all at making something "blow up in the face" of someone that asked if something would work. For me, it does not and this are the reasons. People i play with i ask/make known how i feel about it BEFOREHAND or AS SOON AS SOMETHING UNEXPECTED CROPS UP. We are going to have fun at the table, and fun is for everyone.
It's a "come with the most overpowered broken build you can have" game? Go for it. It's a "this is a serious campaign with my setting etc"? Deal with it (and know that you can't even be a sorcerer, yes there are reason for that, yes we can discuss about it but you are not going to have informations about why or what changes until you are sure you want to deal with it)
