What about usability though? If the navigation was on the right side, it would make it much more convenient to select menu items since the user's mouse pointer

What about usability though? If the navigation was on the right side, it would make it much more convenient to select menu items since the user's mouse pointer is (most likely) on the right side anyway for scrolling purposes. This is what makes blog design themes so popular. But I agree that each has its own place for the type of website (business, education, etc.)