This "preference" has little to do with "jumbo" but has everything to do with pay scale, which is already considered under career expectations. LUAL's opening SLI statement spoke of the "mystique" of 747 flying and continues to use this idea as a basis for gaining advantage. Mystique has nothing to do with it. It's money. In the 90s LCAL had just two pay scales, one for CAs and one for FOs. There was no differentiation for equipment. Using the status and mystique rationale one would expect senior pilots to bid larger equipment for the status even though there was little difference in pay. They didn't. The most senior pilots were evenly distributed from small equipment to large, pilots making QOL choices based on location and schedule. Pay scales were changed to account for equipment, they had a flush bid and lo and behold the senior pilots bid larger equipment, not for status or prestige, but for pay. IOW, there's no magic in widebodies. It's about pay mostly and the whisker diagram is simply showing people bidding to a larger W2.