The chances of becoming main stream of payment within 20 years is 100% possible..
100% possible? oh boy, you need to prolong your post and add some numbers in order to get pay by signature campaign, don't you?

what a bullshit.
in 20 years digital currencies will be much more main stream across the world
it may not be bitcoin itself but it will probably be something that has evolved from bitcoin and rides the wave of change that bitcoin has started