I concur with
judge.oversteer that large heavy a/c have speed/flaps issues, which is to say that having to manoeuvre with flaps extended in order to comply with a slower speed multiplies fuel burn, and after a 14 hrs flight there isn't much "extra" fuel to be dragging flaps.
There is no excuse for non compliance, but controllers should also be conscious of performance constraints when ordering a 747 to reduce to 220kts when 50 miles out.
