I have been fortunate enough to receive several emeralds, two rubies and one diamond over the years (if memory serves) from among anywhere from 10 - 25 breeding pairs at a time. I've traded as well as purchased a few when I found them on sale i.e. reasonably priced, trying to save up for the big prize.
I do understand the frustration of those who have received none or very few but I'd hate to see the Fancies program changed. Personally, I would not send more kitties to the menagerie the chance of getting a jewel. The boxes I keep are kept for a reason and the others are already in heaven so that would be way too big of a gamble for me. Plus, there are other special kitties available for your boxes/menagerie dollars...Confetties anyone??