In analyzing the cause-effect or behavioral consequence for the decline and fall of any cultlike organization it appears to me that the big problem is their non sustainable course of action. They demand of the members an unrealistic submission to unreasonable demands.
A good example of this is signing over all of the advocates material wealth to the organization. Or maybe demanding a donation of 10% of the member's gross revenue for full membership. This could also be the admission price to facilities for the performance of rituals.
This reflects back to what I label as the greed factor. Wherein the lust for gold overrides all other considerations and it becomes paramount to the onward surge of the cult.
Anything that disagrees with the current dogma must be demeaned, disparaged, denigrated, denied, and disposed of. Otherwise it could force a paradigmatic shift and thereby the creation of a new paradigm.
What happens with a cultlike operation is that they pursue this non sustainable course of action. In doing so they Rise, Peak, and Perish.
After peaking new members will still be added but those who leave and are therefore deleted from the population. They will be numerically small but will collectively inevitably overwhelm and consume the group thus enabling the demise thereof.

I think as a high-demand religion, Mormonism will always have a limited appeal. Most people do not want to sit in church for three hours on Sunday, fork over 10% of their income, and be subjected to mandatory "volunteerism," along with restrictions on what they drink, wear, view, etc. It's a tough sell in the best of times.

Of course they don’t want to, but 10% is a combination insurance premium and investment. In this prosperity gospel, you need to be a “good Mormon” to get the payout. So, they promote one of the seven deadly sins (greed) to separate you from your money.

I have wondered if BIC members in particular can see beyond what appears to just be another *given* in their world view.

For example, if I hadn't formally learned about gravity or magnetism, I'd have never given it a thought. In the heart of Utah, until recently (the internet), mormonism must have been just another gravity-like *given.*

When I was eight (in the '60s), I went to visit my aunts. Their Russian friend came over. She took me aside and told me that some of the stuff I was learning in school about Russia simply wasn't true. For instance, yes, Russians could own property. We were taught they couldn't. Of course, there was a lot more, but anyway ...

... anyway, Russia notwithstanding, I never forgot that woman. And what I took away from meeting her was that a lot of information that I was expected to blindly believe became *unsustainable.* I started questioning stuff.

Sadly, I was in mormonism way too long, but when info became available (on sites like this one), I became a voracious reader and verified or dispelled a lot of "truths." I was a convert, though. I can't imagine what it's like for BICs to come to the realization mormonism is a lie, that herking up 10% of one's gross income is more like 90% of their spendable income; and avoiding coffee and tea had no *sustainable* basis.

DR1, I think that you are correct that the leavers will be numerically small ... but will enable the demise of (mormonism).