Yes, but it's not exactly a conspiracy.
Trams are more efficient at moving more people, faster. As has been pointed out, they require people to walk further at each end, however the average overall journey time for every passenger on the route decreases. This is because trams stop less, get caught up in traffic less, and their stops at peak times are quicker, as they soak up passengers through several doors at once.
So the bus route being redrawn to channel people onto trams is basically a function of efficiency, especially down busy corridors like Leith Walk. Bear in mind the council charge the same for the busses and trams, and actually lose money in operating fees versus buses.