Supermot is still quite alive and well where more people actually appreciate motorcycle racing - Europe
Sure flat trackers do, more aerodynamic as well, but check out the Peoria TT where speeds will still reach over 100 on the straight (at least according to what Henry Wiles told us when we ran into him at the Outback Steakhouse after the spring Springfield Mile... great kid):
Relating to another post about some riders complaints of neck strain, it is all in how one carries their head when riding. Stick it up in the air high enough and even a full face road helmet will catch the wind.
I don't, therefore I have no issue. Many don't, thus the reason why a lot of us dual sport/supermoto style motorcycle riders like either the MX or dual sport helmets. They're cooler running in hot weather, the visor is great on bright sunny days, but the MX type with goggles suck when you're caught in the rain. Dual sport helmets work for us in virtually all conditions.
Personally I'm going to get some really close fitting wrap around prescription glasses to fit inside my dual sport helmet so I can easily run faceshield up more often. I'm also going to keep my eye out for a killer deal on an Arai if they fit me well. I'm sold on the dual sport helmet for my kind of riding, though I will still have a street helmet for more extreme cold and also an MX helmet for the hot sunny days.