This is a companion discussion topic for the original entry at http://www.cregox.com/blog/2014/04/why-is-it-so-difficult-for-technology.html
A post was split to a new topic: Por que é tão difÃcil pra uma tecnologia ser algo simples?
I could only figure out what you meant there because of your splitted question in portuguese.
You ask for the title, again. Good catch.
It's a question without an answer. A simple one at least! 
Almost all of our information technology (what people call tech) usually is far from simple and there is no single reason for it.
Maybe we could call it stupidity, but humans are not that stupid. We're more like lost in the middle.
We could call it too much information. The world have about 8 to 9 billion people. That's a fucking lot more than our weak brain can process. We can only really humanize about 150 people. So in here I'm also blaming the brain capacity, but that's what computers are made for - to help minimize that impact.
We could even call it a social issue in which we're not really allowed or encouraged to use tech. It's too nerdy, don't do that, our brain is capable enough and "we only use 10%" right? Not really.
Why is it so difficult? Because it is. Maybe a better title would be "It is so difficult for a technology to be simple. Why, oh why?!". Like an airplane crashing, there are just too many variables to choose only 1 to blame. We must not.
your last paragraph, as in humans we must not choice to blame, could us have a black box , like airplanes?
I think I still don't quite get the question.
a black box is quite simple to use and that's how a lamp works, for instance. you just take it out of the box, screw it up and it works. you don't know how, it just works. very good and reliable tech.
and if you want a black box nobody knows what's inside, just make it bring pure random results. that's still one of my projects... 
ops, now i can not understanding ..
I'm thinking of having a black box for my life, so I die you will lah opens and sees what happened to me
Of course if a lamp I'll know that erased but not why