In my Spring 2011 pricelist, I said that with the USPS change to make all stamps Forever stamps, the need for definitive stamps was greatly diminished. Recent USPS changes reinforce my position.
The USPS announced that it is creating new classes of Forever stamps to pay the post card rate, the additional ounce rate, as well as Forever stamps for the two and three ounce First Class mail rate. With these additional Forever rate stamps, who will ever need definitives again? Almost no one.
I foresee the USPS having a few definitive stamps on hand. For example, maybe 1¢, 2¢, and perhaps a 10¢ stamp. There will be small demand for these few odd stamps. However, gone are the days of twenty or more definitive stamp series like the 1938 Prexy issue, the Liberty, Prominent American, and Americana series. No one is going to need 24¢, 28¢, and 65¢ stamps and all of those other odd rates.
Future definitive series, if there is such a thing, will be less than a half dozen denominations.
One possible side effect of this is that people may take more of an interest in older definitive stamps, especially the postal history behind some of these older, odd rates. You see evidence now that this is occurring in the 1938 Prexy series with solo usages of some of those stamps fetching hundreds of dollars or more because it was a little known rate in effect for a short period of time and there are only a few known covers that illustrate payment of that rate.
The end of definitive series may be a sad event for some. I’m optimistic that collectors will turn to earlier series for continued inspiration.