First of all, even if you are in the cabin/cockpit of a plane with a fuselage of modest length, you should never be forced to endure constant light turbulence or chop.
And for the passengers and crew in back of a long plane, such as a B-757, what is considered light turb. up front is converted into something worse by the swinging around far behind the wings-moderate turbulence due to the fulcrum effect. And if you are in moderate, this can easily become severe turbulence in the back. Why risk breaking someone's ankle or back as they are thrown onto a beverage cart? Do we want our family or friends nauseated for one to two or three hours if we can compare fuel at ETA and have options?
If a Captain is afraid to descend to reportedly better altitudes because of extra FUEL BURN COSTS, yet realizes that he/she will have sufficient reserve+ alternate+decent contingency fuel on arrival at destination and alternate airports, then the Captain COULD BE either a 1) from a totally indifferent corporate culture [apparently quite common?] 2) an inconsiderate %^*& or 3) afraid to put passenger/crew comfort and safety ahead of fuel costs; a wimp or corporate 'kool-aid drinker'. Maybe there are other reasons.
But no critiques are intended here for those cultures with little flexibility ingrained into operational decision-making or having rigid policies on costs.
