Revelations from Patch 7.2: Seekers of Eternity

[Thighland]

Simple: he underestimated us. And has been underestimating us, constantly; Endless Sphene by all respects would've been just fine as a custodian for the key, until Wuk Lamat and ourselves turn up; until we turn up there's not really any problem at all with Endless Sphene as far as his purposes go. Once it's clear we're not exactly giving back the key voluntarily, he hits us with a lightning bolt powered by a whole city... and that doesn't work. Then he throws us into the Valia Pira test battery, and that doesn't work. Then he throws Zelenia at us, and THAT doesn't work.

Underestimating us and our fighting strength is one thing, but he should have known that there was a possibility that Endless Sphene wouldn't do what he wants (she is his creation afterall), which is the actual main reason why we have the key, and he doesn't. But maybe the writers didn't think of that.

I don't think he has an 'unreasonable obssession' with Sphene, so much as he recognizes that Sphene is the beloved Queen of Alexandria, and that itself has power; if Sphene asks someone in Alexandria to do something, they do it. I do still think there's probably a level of duty, but again, not to an unhealthy degree; Calyx's original goal was to solve the very illness that faced Sphene, so I doubt he ever did the thing that confirmably gave up on it. It's like the high-stakes version of never throwing away that guitar you kept meaning to learn.

Using Sphene as a mere tool to keep the Alexandrians docile does make sense, but I feel like the incentive for that falls apart when you realize that the regulators enable Calyx to control the memories of the people at will, and by extension the people themselves, making the need for a figure like Sphene practically obsolete, at least after such a long time. And we know that he has no qualms about using the regulators in that way, not to mention killing his own people. Again, this could be a writing issue, but if it isn't, it seems pretty out of character for a seemingly pragmatic person like him.

Concerning the levin sickness, my personal impression is that he never really wanted to cure it, or if he did, he changed his mind a long time ago when he got the idea of taking mankind's evolution into his own hands.
Are Beq Lugg and Owen the only ones capable of figuring out how to cure a tempered soul? Was Calyx, an expert at handling souls and memories, really incapable of figuring it out after hundreds of years and with technology that, at the very least, rivals the Allagans? I don't buy it, but in the end there's nothing else to do than wait for confirmation I'm afraid.

(Excuse my constant arguing, I actually enjoy this discussion a lot)