The 16 gauge philosophy is about balance. Balance between smaller and larger. Balance between length and breadth of the shot column. Balance of the gun in the hands. Balance between having too little gun or too much to carry all day. In America, 16 gauge guns are best suited to the uplands (If you think 16 gauge shells are hard to find, try looking for them in steel
)The magnum philosophy is power. Getting steel (with it's rapid energy loss when compared to lead) to retain a descent terminal velocity requires power - 3 1/2" magnum power, if you want to extend ranges. Unless you enjoy beating yourself up, the guns chambered for magnum loads ought to be much heavier, to absorb the energy released by the magnum loads (especially since carry weight is seldom an issue in the blind).
The shotgun shell manufacturers are putting their investment where the market is well defined. What they're not nearly as good at is seeing what markets could be. At a time when all manufacturers want to find new models that will sell, you'd think someone would notice the unfulfilled classic SXS market and the sub-gauges in general. The Turks were the first* to wake up (selling under a variety of brand names). But, so far the rest are still asleep at the switch.
* Appointing a "first" is heresy at best and foolhardy no matter what. Ruger was ahead of the Turks and every arms-producing nation on Earth was ahead of him, but I'm just talking about the last decade.
