“The problem with that is that the crashes were all hidden from the public except for the brief newspaper story in Roswell in 1947.”
Yes, and it worked. They let the UFO enthusiasts run with and do their work for them. Everyone was looking for aliens while the truth was right in front of them.
The “alien” craze from the late 1940s and 1950s was based on real experiences from real people.
You may not believe that—but that is the way it was.
Here is one example:
https://en.wikipedia.org/wiki/1952_Washington,_D.C.,_UFO_incident