The whole “alien” narrative that exploded in the 1940’s and 1950’s was for the purpose of covering up the U.S. government’s involvement in physics bending scientific research. The Manhattan project never ended.
They need to continually bring in new physicists to develop the tech and the way they keep them quiet is to tell them...
“This is alien technology that we want you to help us understand. You can’t tell anyone that we could provide unlimited energy, faster than light travel, etc... or else they will freak out, create mass hysteria and lose their religion. You will be the good guy for keeping this secret from them.”
The powers-that-be retain their control over the energy/defense/banking industries and everyone is happy. (except the people who are stuck living 19th or 20th century lives in the 21st century.)
I agree with your general point—that is the concept of Richard Dolan’s breakaway civilization.
However—I do not think this is a case of either/or.
I think it is both.
The Deep State is playing catch up on legitimate non-human technology.
Richard Dolan, Joseph Farrell and the Dark Journalist (Daniel Liszt) are solid on this topic.
Most of publicly known science is obsolete trash—as Terence McKenna said “designed for making toys for well behaved children”.