Do you think the church would somehow go against some very basic priciples of belief to save itself from declining membership?
Sure why not? Aren't the official manifesto and negroes holding the priesthood examples of that? At first the line was that polygamy was a true principle that had to be taken away because if it stayed the Church would die. Now polygamy is completely off limits as a topic, so as a true principle, it's not even taught anymore. When reporters state, "The Mormon Church no longer condones polygamy," the brethren are happy it is portrayed this way. How is that not a change?
Do you think a declining membership will be attributed to a weeding-out process adminstered at a local level?
Sure if you're talking to the people on this board. But in a mission conference it would be due to lack of faith, lack of sacrifice, and the weakness of the missionaries. It's due to low home teaching if it's the stake president talking to the elders quorum but the members tolerance for that line of thought is diminishing in my view. I don't really see this as something new that is happening. Missionary and retention efforts have not been based on doctrinal superiority but rather interpersonal relationships for many years now.
Do you think nothing much will change?
Things always have changed. Even the Church admits this to an extent.
Do you think the LDS church will surpass many other churces in growth in the next few decades?
No I don't, but I don't see why this is necessarily a problem with respect to Mormon Doctrine. Even the Book of Mormon states that the numbers of the Church of the Lamb were few in comparison to the numbers of the great and abominable church.
So what if 80% of the members leave. There's still an enormous amount of money in the Brethren's bank accounts. Doesn't that cement the Church as a force for some time to come.
And when the confederates saw Jackson standing fearless as a stone wall the army of Northern Virginia took courage and drove the federal army off their land.