This is an interesting point, and I can kind of see the outline of some vaguely political reasoning here. Let us clarify that we are talking about realtime rend

This is an interesting point, and I can kind of see the outline of some vaguely political reasoning here. Let us clarify that we are talking about realtime rendering for games. Of course, rendering in general has been done in all sorts of different ways, and it's pretty straightforward to demonstrate a raytracer that progressively enhances is rendering over time. The point is, this isn't a direction that cutting edge games programming has gone in, because getting more detail into the game has always been a higher priority than having a steady predictable framerate- And to make a further point, practically speaking, painter's/z-buffer algorithm is easier to optimise than some other rendering algorithms. Though, the others are not impossible, just not fruit that is quite as low hanging.