What makes a boss tell you that you should not try to go beyond him even if you know more than him?

1) It may depend upon the way of presenting the new Idea or innovative idea infront of the Boss.
2) Identification of right situation of presenting oneself is more important 3) Interest should be shown in differents aspects of function so that Boss may understand the broader learning interest of the employee.

Sometimes it is by reason of chain of command and position.
The boss needs to know that his employees respect him/her.
As a leader to remain control and effectively move forward everyone must be a team player even if you are more knowledgeable.
There is a chain of command that exist and must be followed.
This system exists in order to control chaos.
Whether you as an employee may like it or not he/she was chosen in that position and deserves to be respected because of the office he or she has obtained.
There are occasions when the boss is simply threatened and in such a case will stifle anything that poses a threat to his or her authority or position.
Be wise in discerning and disseminating the exact cause.

may be you know more than your boss but you mention a bad type of boss A good boss get his employees know his strength A bad boss thinks that s/he is the only one who can perform a given function