Some Pro players will indeed attempt a kill shot on the return. But not a drop shot, as there is essentially no way that it can be played tightly enough that a fellow pro, in position on the 'T' following their serve, will not only retrieve it but get to the drop sufficiently comfortably that it will gift them control of the rally.
The kills you will see tried are looking to put the ball across court, short and into the nick (this is key), but it's played as a power rather than a touch shot (also vital). This is a shot a number of the leading Egyptian players, male and female, go for fairly often. And me, sometimes, at my much lower club level of play with consequently much reduced success! ;-)
As for the philosophy part, the biggest difference between the pros and amateurs is not shot-making but fitness and movement. Their shots might be only twice as good (four times, five times, whatever) as a club player, with their speed around court five, ten, twenty times improved. That makes it a lot harder for pros to play a winning shot against each other. So in response to the specific question "If elite players (not me!!) are capable of making a well-placed drop shot and ending the rally, why don't they?" - they do, whenever they can! But they (or more like their opponents) are in a position to allow a winning shot, any winning shot, much less often than club players.