There are plenty of business theories around, but many either never worked or no longer work. The popular theories of the text books at many business schools provide outdated theories that were questionable at best when they first were dreamed up. Experience will always trump mere theory and speculation.
Music Credit:
“Relaxing Piano Music” Kevin MacLeod (incompetech.com)
Licensed under Creative Commons: By Attribution 3.0 License
http://creativecommons.org/licenses/by/3.0/