Frozo
I'm surprised you don't agree with text books.
Really, why? Do you think that because someone has their thoughts and opinions published in a text book it makes them infallible and their theories somehow become accepted fact? If you really think that then that explains your very theoretical take on industrial dynamics.
There are many accepted economic theories, they cannot all be correct. They are usually theories constructed to answer a specific question or address an observation and most fall apart when put to the complexity of a real world test.