The “Crusades” that really matter to modern Muslims were those since the French Revolution, since Napoleon landed in Egypt in an attempt to establish French control in the region. By 1930, the Christian Powers were in the ascendent everywhere in the Middle East and in the Med. Only Turkey and Iran maintained their independence, and this by modernizing their society.
All of this has been rolled back as a result of World War II and the collapse of the European Empires. Ironically, American anti-colonialism contributed to this and our attempt to fill the void, especially after the Suez debacle, was been imperfect. The Europeans socialists accuse us of imperialism, not recongizing that it is precisely our dislike of imperialism that has weakened us. We blame ourselves for the inability of the Muslim nations to develop a growing economy or a rational poltical order, despite the huge returns the Middle has received from its near monopoly of the oil supply.
IMHO, the invention of the combustible engine and the almost simultaneous discovery of oil in the Middle East and N. Africa changed the geopolitical landscape. Both World War I and World War II devastated and weakened Europe and in effect, destabilized the Western world.
Some argue that the Allies access to oil in WWI was the decisive factor for Allied victory.:
http://www.saudiaramcoworld.com/issue/199901/prelude.to.discovery.htm
“The decisive difference between the allied forces of England, France and the United States and those of Germany, Austria-Hungary and Ottoman Turkey was thus not so much tactics or even leadership but oil supply. In addition to Anglo-Persian—which by 1916 was supplying one-fifth of the British Navy’s needs—the Allies had at their disposal the giant networks of Royal Dutch/Shell and Standard Oil of New Jersey. The Germans were less fortunate. When the Allies destroyed the oil facilities in Romania in November 1916, and then prevented Russia’s Baku fields from falling into German hands in August 1918, the war was unsustainable.”
Changing demographics such as population and the declining birth rate in Western nations has played a role too in the decline of Western influence in certain parts of the world.