Walkman,
Your question is valid. The best way I can explain it is to break this down into specific price points. Lets say you really enjoy the Hawk's and decide to bring a pair home. Now, you may need some decent electronics that form good synergy with the speakers.. but many (most) are not afforded the luxury of price-no-object spending. So at the bottom tier of good electronics that form a good synergy with the Hawk.. we may look at equipment from the likes of REGA - a Mira 3 or Planet 2000 could be purchased new for in/under 1k each and at that price point for both components used. For that price-point, you are achieving great synergy with the Hawk. Will it sound good? Certainly. Will it show off what that speaker is fully capable of? Certainly not.
Apply the same logic/principle the further up the chain you go. The Sim (or Plini) piece are proven to be fairly good matches with the Hawk given their price points (2g-3g new, 1500 or so used).
There is a ceiling with all equipment to where you begin to hit the laws of deminishing returns. That applies to all products and may vary on a per person basis for a plethora of personal reasons.
My statements tend to lean more on the bold side of things, but they are there to let people know that this speaker in particular is quite capable and indeed enjoys electronics a notch or two above the usual mated suspects (sim, plini, unison research, naim etc.. )