Is the reason that condy has been in power so long is not just that she is more powerful than any heiress that has been sent to fight her, but that the crown/circlet can mind control the heiress to not put up a fight and get culled. The only evidance that I have is jane's tiaratop was able to infect and mind control her when condy put it on her.

Yeah but Jane’s Tiara was a Crockercorp Tiaratop with its own unique design, there’s nothing to indicate any other Heiress was under any sort of Mind Control at any point. Not to say, Jane is a Human, and the other Heiresses would’ve been Fuchsia Blooded Trolls which likely adds a layer of resistance. If you want to blame anyone other than Condy being Cunning and Good at being an evil Tyrant, you could blame Doc Scratch vaguely influencing things to ensure Condy isn’t dethroned.