In a world where so many people now have access to education and cheap tools of innovation, innovation that happens from the bottom up tends to be chaotic but smart. Innovation that happens from the top down tends to be orderly but dumb.
– Curtis Carlson
Geoffrey Graham 
Sounds like bottoms-up innovation is more driven out of lots of iteration and trial and error where good ideas survive/thrive and bad ones (most of them) linger in obscurity or die quickly. It’s an organic/evolution-based style of innovation (methinks).