I know little about physics, but this seems really simple to me.
ON FLAT, you expend a certain amount of energy to defeat wind resistence and friction to move forward
ON INCLINE you expend a certain amount of energy to defeat wind resistence, friction and gravity to move forward and farther from the center of the earth's core.
So with an equal amount of energy spent you will move less distance on an incline.
About climbers
If someone had a good ratio, and was fit enough, would they necessarily be a good climber?
This is probably 75% of what makes a good climber good. The other 25% is probably a mix of other vital statistics, (VO2max, LT, pain threshold)
NOW heres a question I would love to get answered, why do us fat people blast down hills way faster then skinny people!!!