I have the privilege of working for both departments in various organizations. What I saw was an inherent tug-of-war between the two departments. If the products sells, Marketing rushes to take the credit that it created pull while Sales say that it was because of push.
If product fails to take off, Marketing blames the Sales of not pushing the product and Sales accuses Marketing of creating no pull. The blame-game is conspicuous in organizations where each department has its own Head reporting to COO/CEO.
When objectives of both departments are the same then why there is lack of synchronization and harmony in the working of two vital departments and how a convenient marriage can be arranged between Sales & Marketing so that there is harmony and smoothness in the way of achieving objectives.