Mongol invasions turned the remaining Crusader states from useful trading partners into a strategic liability for the Mamluks.
The Crusades produced an commercially interconnected frontier society; the Mongol invasions destroyed that balance, replacing with a defensive state.
It was a profound reorganization of the Levant, not just ending its civilization or prosperity, but shifting who governed, priority interests, and how cities, countryside, and coasts related to each another.