Not a much curry consumed in this country, so it very well could be because they sit on the shelf longer over here.
In any case, the missus and I used to have curry night once a week. I bought a cookbook of
50 curry recipes and made a different recipe from the book every week for a year (well, a couple weeks short of a year I reckon
). There was enough variation in the recipes that we never grew tired of it. I only had to buy about a dozen or so different spices that covered almost every recipe. It's amazing all the different flavors you can get by switching up just a handful of spices.