Experience does matter, but what you have learned from that experience matters even more. The Syrian Army had 13 years of war fighting experience. What have they learned? Helicopters picked up US collaborators from the rooftops of Saigon in 1975. Then they did it again in Kabul in 2021. What have the Americans learned? India had more recent combat experience than China, but their Jawans were routed at Galwan 2020. What have the Indians learned?
China doesn't have recent war fighting experience. But it is constantly learning by observing other people's experiences. They've watch what had happened in 1991 in Iraq, and in 1996 in their own waters. Since then, they've been striving to build a brand new military.
What have the Americans learned since 1991 and 2001? They have learned that wars with smaller nations are more fun and that these kinds of wars are good business. They've learned to optimize their military towards smaller and smaller conflicts. They've learned to make more money for less. Gone are the days where America could produce tank divisions. Now they want to produce premium systems at low production rates and sky high prices. Much of America's true formidable strength lies in legacy systems that were brand new in 1991. When these systems are attritted, they cannot be replaced in a reasonable amount of time, and some are even irreplaceable. The new systems can't come online fast enough.
America have learned from it's war experiences to build a military of luxury. While China have learned from no recent war experience to build an actual military that can stand against a Superpower.
