The U.S. Mint has reduced the mintage of the 50th Anniversary Silver Kennedy set to 225,000. Originally it was 300,000, but sales have been very slow. The last figures I saw indicated some 165,000 sold, which isn't even the original 180,000 struck in anticipation of demand.
Part of this is undoubtedly the high price. At $99.95 for little more than an ounce and a half of silver, this is certainly not anything with any intrinsic value. It does have one unusual coin in it - the new enhanced uncirculated coin - which may eventually become a semi-key for type collectors and Kennedy set folks, and of course the silver content of the other three coins could make them important for the same reason, but it may be a long time before these are of general interest.
Reducing the mintage will help, I'm sure, but unless the Kennedy series ends, I don't think it will matter that much. There probably are not even 165,000 people interested in these coins as collectibles; most of the purchases were for "investment".
How long before we stop making Kennedy halves? Unfortunately, for political reasons, it's very hard to stop. Who will vote to do this? It's hard to image anyone daring. So we'll keep making coins that almost no one uses or wants. We MIGHT be able to rid ourselves of Roosevelt dimes and Jefferson nickels, but the rest we are stuck with for a long, long time. Depressing, isn't it?
Note: All my coins are in a safe deposit box. I keep nothing in my home.