The USAF used scarce data on the Mig26 Foxbat to justify the amazingly expensive F-15. But the Foxbat could reach Mach3+ (ruining its engines in the process). The USAF claimed if it could do that speed it could also do everything including walk on water. In reality it was a crude airplane of limited capability. A purpose built interceptor for the B-70 which was never built.
If the Chinese did in fact do what they claim many heads should roll at DoD, CIA and NSA. None will. The Pentagon and White House are too corrupt
Mig25.