The guy who recorded the fastest time in the Great Southern Randonnee over 1200km last October was on an MTB with slick tyres and MTB gearing. Something like 58 hours for the ride. Nice young guy, too.
Many are the people who ride MTBs to commute. They don't want another bike either. The gearing is just fine. Many are the people who have done trans-US and trans-Aus and trans-whatever-other-continent you wish to name on MTB-style bikes. In fact, one of the biggest-selling English touring frames is the 26"-wheeled Thorn Nomad, then the Expedition, with... guess what... MTB gearing!
And why don't you post your reasons, Jay, for absolutely dismissing MTB gearing for road gearing... I'd be interested to know, too.