I would say absolutely not, and actually, given proper Equipment, Wind consistency, and Currents, it is very very easy.
Now, below 10knots, things get progressively more difficult, and every knot becomes a conquest
Equipment: If I can foil easily in 10 knots (not talented, super heavy – 115kg suited, and a novice with less than 1 year experience of kitesurfing) than anybody can! Forget the smiley: I'm serious. If I can, almost anyone can.
But equipment matters: in my case, I only made fast progress when I switched to Airush Ultras (especially the 17m) from previous beginners' three strut very heavy kites, which loved to fall in the water at every mistake, and were impossible to relaunch (for my abilities, that is).
The Ultras simply don't fall from the sky, even at lulls: a loop is almost always enough to keep them in the air even when there's almost no wind. (of course, to learn this, I swam a lot! ), and are easier to relaunch. Having had Airush I bought the Ultras, but am sure many others are perfect too for this.
And with a 17m Ultra, I'm good to go from 7 knots.
A pal of similar abilities, 10kg less, same hydrofoil (we both use the Onda 633), but a Soul 21, has circa a 1 knot edge on me – when' I'm just at the very limit but can't start, he is usually foiling... just )
A 30kg lighter, more experienced kiter, once tested my kit in 5.5 knots indicated, and he foiled. I was astounded, as on the beach we were wondering where the wind was...
For me, with the 17m and 10 real knots, the moment I steer upwind after waterstart the kite feels like a freight train, accelerating exhilaratingly. Sounds crazy in such a low wind, but for a second or so, it just wants to rip me of the foil
Wind: as others have said, wind consistency matters.
At my local spot, South, or SouthEast winds are not very reliable, maybe showing 8-9 knots with lulls at 4. It is exceedingly difficult (for me) to foil, and even if I succeed, it's very easy to lose the kite at the first mistake during a lull... and swim.
But West, or NorthWest winds, even at 7 knots, I just let the 17m "fall" (it really does that), than gently recall it a bit, and the kite will pull me out of the water pronto and get me foiling without a thought.
Currents: too much current downwind will sabotage kiting. Lines become slacker, usually just enough to prevent a waterstart.
Maybe more experienced kiters solve this with looping, but honestly, I am still not able to do it, so low wind + wrong current = no-go for me...
So I stand by what I wrote: real 10 knots, appropriate equipment, not too much current, and everyone will get foiling...