Good observations and I've observed more than a few in computerland, especially in startups.

However, it's not true that cult leaders are always grandiose. They can be strategically vulnerable too!

When confronted -- especially by someone too smart to be fooled by their facade -- they can take that critic aside, in a private setting, and suddenly express vulnerability, maybe even fragility. The critic is taken aback, maybe even worries that they've gone too far, but also feels honored to have become a confidant of the leader. The critic may now even feel compelled to help cover for the leader's failings!

But this, too, is an act. Remember, as Sasha said, such people are always being strategic, and strategic vulnerability is part of how they operate.