I think Sun Tzu said something like: “Don’t stretch your supply lines”. My understanding of the Crusades say that is the main reason for the failings.

It is amazing that the Crusader Kingdoms lasted as long as they did. But between the Christian/Muslim wars, there was actually a fair bit of business interaction. The Muslims liked the wealth that was flowing from Europe to Palestine. And they were fighting amongst themselves as not to be too concerned about Christians occupying a thin sliver of land.

For sure, the Christian pirates were not helpful to the Christian objectives.