D800: Why not tilt/swivel screen?

Why is Nikon so reluctant to put a tilt/swivel screen into their pro/semi-pro bodies? It seems (by the rumored pictures) that D800 won't have one. In the Nikon line only the entry-level D5100 has it.

Why not? Is it a gimmick? Another part to be broken? Doesn't look serious in a pro/semi-pro cam? Those excuses don't make any sense to me, because it would be very useful for angled shots and movies, and the professional Olympus E's have had it for years, also the future full frame Sony a99.

I hope the D400 could have a tilt/swivel screen. Would cost nothing to Nikon and not lost any sales, quite the contrary.