This is a serious conundrum. We have been brought up in this environment, this box, and we live in this box. Even our very thoughts and motivations are essentially in this box This is the box of ourselves and there is nothing outside of that box of our lives.

... is it surprising that people will defend it, irrationally even?

Get out of the box and view it from the perspective of those outside it to begin with.

You can say that, but it is hardly possible. The box is you.

... usually, the only way out is some sort of severe trauma - or mind-altering substances.

Maybe in one context but if you think that there's only one possible system then you're stuffed. See how other systems work and how your system is perceived by others. Then you have a chance.