My impression is the Westerners’ best guess about the Mig-25 contributed significantly to the design of the F-15 and helped to make it what it is. Getting their hands on it was a relief, or even a let down.

The alternative scenario, where the Mig-25 really was generations ahead, plays out in the movie Firefox from 1982 where the US is so far behind they have to steal a Soviet Mig-31 superplane. Good for laugh today, but once upon a time…

The rumor I heard is Soviet intelligence infiltrated American industry and stole what they thought were plans for America’s next generation air superiority fighter. What they’d obtained were the plans for Plymouth’s Roadrunner Superbird, thus the Mig-25’s uncanny resemblance. Proof: https://robbreport.com/motors/cars/1970-plymouth-superbird-a...