We may have had technology for quite a while that could make things appear to be there when they weren’t.
I have a SSDD drive for my computer/cellphone/camera gear that is the size of a pack of cigarettes but only as thick as a pencil that holds 15 TERABYTES of Data. I don't think I can imagine what 15 Terabytes of data would would comprise. You put everything I ever heard,smelled, felt,learned, said my entire life and I doubt the capacity gauge would barely flicker.
We have equipment that can see completely through walls. Back in the 80's the Russians developed a satellite that could project Neutron Beams at another satellite in orbit and send it crashing to Earth. The Russians were so kind as to actually demonstrate it doing so, right over the United States. The MSM never reported that to the US Public.
Many times were are not privy to tech breakthroughs. Those that try to go public with major discoveries or advances, without permission, often die suddenly.
All that aside, being able to control the minds of individuals so that you can make them see things that are not, and not see things as they are is where most of the investment in technology has been put
It has been in demand since Adam and Eve's children got in a fight. Most of my life has been at the mercy of this desire to control others. The most dominant being TV. It's why they call it NETWORK PROGRAMMING.
Why is it, though, that the one's who want most to control others, have no control over themselves ?