kid, Roman catholicism happened, and with it power hungry clergy that literally burned all the knowledge that was accumulated from the Greek times onward.
In this heap of knowledge were ofcourse included earlier discoveries from the civilizations in the fertile crescent
(Eufrates and Tigris river), but Greeks and later after them Romans contributed to this heap as well.
Standing army concept was done by Romans, they had a standing army of proffesionals on 20-30 year contracts.
First contact with eastern civilizations didn't happen in the crusades but when Alexander conquered everything up to India. Roman's had colonies in the Middle East as well.
Peak of Greek engineering would probably be the Antykitera mechanism.
Antikythera mechanism - Wikipedia, the free encyclopedia
Cannon technology advanced so fast in the west the siege of Constantinople was done with cannons that were made by a Hungarian gunsmith.
While it is true many contributions you listed were created by easterners, none of them utilized them and improved them in such a way that fused everything together.
Example, compass, gunpowder and improvements in sail and shipbuilding technology resulted in ships that could travel reliably and predictably across vast distances, where every such attempt in the past was just a one off attempt that never lasted
(Vikings in America, Zheng He to Africa)
Another good example would be the printing press, Guttenberg made his own contributions to existing knowledge which made possible printing in mass. So actually being usable rather then just a toy for rich people.
Thankfully, we have now all but fully abolished the plague that is called organized, politically active religion.
