I am sure Russia and China have lots of spy data but it's a completely different ball game to gather data in actual combat, not some dopey exercise, and to collect pieces of an actual aircraft for materials analysis, etc.
I am sure the Chinese had plenty of spy data on US stealth helicopters but they were still eager to get parts from the crashed Black Hawk in the 2011 Abbottabad raid.
Pakistan allowed China to examine the remains of the US stealth helicopter downed in the raid on Osama Bin Laden, US officials believe.
www.bbc.com
He said Chinese engineers were allowed to survey the wreckage and take samples of the "stealth" skin that allowed the Seals to enter Pakistan undetected by radar, according to the paper.