Why is there no, Dune FPS game?

We know that there is a upcoming MMO fps game for Dune, but why in the past or the present there is no actual FPS games for Dune?

A first-person shooter sets, in the Dune universe a-la Jedi Knight and Half-Life style would have been amazing most of Dune games in the past were RTS games and a action-adventure game based on the mini-series.

So how would you imagine, a Dune FPS game?