Presumably so that people will buy the Brickmaster magazine.
That's silly. Now they have a smaller pool to pull the winners from = the winner probably won't be as good as it could be.
BtB
acctually, a smaller amount of competiton means there is more of a chnce, so thik of it like this:
what is the better ratio(estimated):
1:10,000,000(normal mag)
1:10,000(brickmaster mag)
now do you see?
oh, and also less entries=less work for lego