That's because of a lack of education, because we, the technically inclined people, have failed to serve the normal people, preferring instead to:
1) reinvent the wheel over and over, each time with a new interface, shinier and more limited than the one before it
2) cater more to our hypothetical grandmas instead of our children ... which ironically are able to write HTML in Notepad just fine, if taught how to do that
Users don't like our convoluted, hard-to-use
systems and have abandoned them for products
that are easier to use
What you're missing here is that those products
that are easier to use get replaced like socks, with the users being back on square 1 every single time and struggling to perform even the most basic tasks by clicking their way around.
People all over Europe have learned to drive cars with manual transmissions - because after the initial pain, the vegetative nervous system kicks in and the wheel, the pedals, the gear switch, all of them become a natural extension, of which you don't think about anymore, just like breathing. And if automatic transmissions are great too, that's because they stay out of your way.
The UI of modern software is nothing like that. Nothing is logical anymore, nothing is designed anymore to be an extension of you. Normal users have to think about their every action, they have to visually search for clues in the UI for every stupid thing they do, they have to rote learn the paths they have to take for the software to take them from some point A, to some other point B. I saw users that have notes on the actual clicks they have to make for certain common actions. I don't know about you, but to me this is freaking painful to watch ;)
Btw, for some good user-experience guidelines, check out The Design of Everyday Things: http://amzn.to/ryfiuI (the link does contain my affiliate code) ... the one thing I took away from this book is that simplicity is a complex topic.
Why won't people do more work ...
setting up their own blogs
Setting up your own blog is just a few clicks away on Google's Blogger, on Wordpress.com, on Tumblr.com or on countless other services. It takes more work to set up a template that represents your style, but that's not something you can do on Facebook anyway.
Really, step down from your high horse, it's not like you yourself are not guilty for the current state of our industry. We all are.