It's not just in the US that cake decorating has taken off..it's worldwide. Even in Asia where it's not in their culture/history to bake cakes (most local homes don't even have ovens)- now all of a sudden everyone and his cousin are 'bakers'. It's incredibly trendy here and we have extremely low unemployment and not the same economic issues as in the US.
There have been tons of home bakers, decorators, classes (for a lot of $$$) popping up eveywhere. I think the cake TV shows from the US had a lot to do with sparking the trend, and the 'allure' of getting 'rich' by being your own boss. (ha!) But I've heard people say "well if I can only make a couple of $1000 cakes per week......" not bothering to factor in the real cost of doing business, the effort of working that much or even getting a customer per week like that....
Also the new designs/styles of cake decorating are perhaps more appealing than the older styles? I know, for me personally, I only am interested in making/creating something new and modern and not at all the older designs/styles- even from the 1990s, just are not interesting to me at all.
Clearly there is better money in teaching ($800-1000 for a two day class!) then selling cakes or else they wouldn't be doing it.
I've noticed some of the new decorators are really good artistically and some are not- at all..and despite that there seems to be a market for both.