Have attention spans gone to hell, or have we just learned to focus on attention spans as being a problem?
I think it's the latter. It's like everyone now saying, Oh, I have a little ADD.
Bullshit.
You are born with a seven second attention span, just enough time to focus on something and decide whether or not something benefits you or not. An example of this is music videos. They are designed with no video segment longer than that so that at least every seven seconds your brain is subjected to another video sequence which you automatically watch. If the segment was to run for much longer you would realize that it is not interesting and would look away, but the advertizers want you to keep looking so they flash on another segment which you watch.
But of course you already knew this but forgot seven seconds ago.