User blog comment:Dettles/Why didn't Marco protect whitebeard's terrorities?/@comment-4754162-20130602081121

Its true that INDIVIDUALLY they are strong enough, their respective prowess confirmed it (Marco vs Borsalino / holding back Sakazuki for a while, Jozu pinned Kuzan down until distracted, Vista almost on par with Mihawk) but without a proper leader, they will not be able to win strategically.

The absence of an experienced and able leader should be the answer to your question there.