IMHOThat could be the conventional way to measure, have you considered whats stopping us from having full tilt so to speak at our minds powers not just for a few but for all humans?
When we are born and possibly up to a certain young age,
our minds keep searching for the existentialism of our own creation,
which is not unlike the wonderment of seeing something for the very first time.
We are in tune with that unseen something , that peculiar feeling from within that there
is something more than what we are seeing....All around us.
Ever heard someone tell you something like,
"when I was much younger, I could train my mind to do things...I controlled my dreams....I saw spirits....
I answered the telephone before it rang because I knew (so and so) were calling.....etc....etc"
But,
As we grow older and accrue more and more responsibility, data, every day information,
we take on the worries of adult life as we navigate towards maturity and ageing.
As we do, we lose what we once had because we are shaped into the norm by life itself.
Loss of Innocence is not quite the answer as is perhaps that 'New Self Purity' we all are (or were) when we are born.
Thus the myriad of publications for sale involving getting back to that mind/state.
Just my two cents here.
Does this help explain?