The most telling evidence that the population at large cares not a wit for the 16ga was on the store shelves at a recent closeout sale I attended in upstate NY. There were piles of only 2 types of ammo left: 7mm STW and 16gauge shells of all types. 16 gauges are for collectors who already own 10+ shotguns, or those who write for gun magazines. Reloaders and even factory loads have already brought the 12gauge down to nearly 20 ga performance (witness the 7/8oz loads sold at Walmart). There is no more performance gap between the 12 and 20. Add in the lack of a lighter gun available for the 16 and you begin to hear it's death knell.
Leave it in the past with the 24ga, 32ga and arguably even the 28gauge.