Regardless, you're whistling in the wind here. 'Beth-lore' is that the Temple collapses. There's even a plausible explanation. Vivec said 'I'm gonna tell the priests the game's up, and then I'll head off to some other dimension to chill'. He does this, subsequently Lexie and Sil die. He sees no point in not letting the priests know, tells them. This is basically what the game suggests happens.
That Vivec told the populace is the only even semi-plausible explanation, but from the 3rd PGE we can easily infer that that didn't happen (and nowhere does the game basically suggest that it happened):
"Dagoth Ur and two members of the Tribunal, Almalexia and Sotha Sil, were destroyed in the Nerevarine's fury. Vivec too may have been killed, but his fate is currently undetermined."http://www.imperial-library.info/pge3/morrowind.shtml
They don't know what Vivec's fate is or whether or not the Nerevarine even killed him, so I'm pretty sure we can say for certain that Vivec hasn't been making any public announcements - afterall, if he'd been the one to relay the news of Ayem & Seht's death then surely they know he whether he was alive.
So, what do we come away with. Vivec didn't tell them based both on the above quote along with the fact that doing so would openly contradict his goals. Helseth & the Queen Mother are the only other people that knew, and they wouldn't be believed; the people already think he killed his predecessor, he's known to be at odds with the Temple, and he's a foreigner, not exactly a good source regarding the state of the Tribunal as he's obviously biased and untrustworthy, plus if the people won't believe the Nerevarine they're not going to believe Helseth. The Nerevarine is the only person that could provide proof as he's the only one capable of accessing the Clockwork City, but it can't be waived off as the Nerevarine having done it simply due to the fact that the Nerevarine didn't canonically do anything outside the Main Quest. So basically it couldn't, wouldn't, and shouldn't have happened the way the devs say it did.
An argument suggesting that this is impossible is a rather hopeless endeavour. 'The Lore' clearly states what happened, and even justifies it. You could argue that that's not a good story, which, as I said, I agree with you on, but you can't argue that that's not the story.
I never argued that it wasn't the story. My entire premise throughout this thread has not been that it didn't happen, but that it shouldn't/wouldn't/couldn't happen if the devs had actually thought it through.