It came out in 1969, around the same time that Walter Cronkite was explaining on his science program "The 21st Century" how wonderful-- and sometimes how awful-- the 21st century was going to be. That song reinforced the "awful" aspect to me.

For as much as they got right, there was quite a lot of creepy dystopian stuff out there too.

to see what Walter Cronkite got right.

By the way, that song prompted me to make my own predictions, in 1969. I don't remember all of them now, but I do remember that I predicted that Dallas would get a professional baseball team in 1972 (as it turned out, that was the year the Texas Rangers came into being) and that the Vietnam War would end in 1975, with South Vietnam winning (call me biased on that one, but I did get the year right). The other prediction I remember was that sometime in the 3000's, humanity would be wiped out and that ghosts would be wandering the earth.