For all the same reasons that the Old Course at St. Andrews still plays tough, so does Garden City:
1. Greens that slope away and that have no back wall.
2. The fairway bunkers are relatively small in size and thus more penal than big modern bunkers where you can oft times be so far back from the lip that you can still reach the green.
3. As a true minimalist design, judgement of depth is very, very hard to achieve on an approach shot due to the lack of greenside framing and thus a member at GCGC has a great advantage over the majority of us.
4. Thanks to the tree removal, wind is once again a key factor as it sweeps across the Hempstead plain.
5. A superb Eden hole
6. Half par holes like 1,4, and 17 where a double bogey lurks just as easily as a birdie. Like the 12th at St. Andrews, the big hitters of today can't help but give such holes a go...and that's when the fun starts.
7. A truly wild drive can be severely punished in some thick, tough stuff.
8. The severe pitch of such greens as 4 and 15 will always keep a man honest.
9. The aerial game still hasn't diminished how the golfer must use the area around such greens as the 16th to work a ball close.
Cheers,
PS Unfortunately, it also plays hard because of the mongrel 12th green but I'm sure that is being fixed soon.