The decrease in astrology's visibility (people no longer read magazines, and "horoscope blogs" don't seem to have become a thing) may just have led to most young people not having a clue and assuming astrology = astronomy.
Sure, "spot on" is obviously stretching it, but considering the time scale I think he did really well - I doubt anyone today would be able to predict 2064 equally well. Some good examples from the original article:
State of robotics: "Robots will neither be common nor very good in 2014, but they will be in existence."
State of space exploration: "By 2014, only unmanned ships will have landed on Mars, though a manned expedition will be in the works."
Smartphones: "Communications will become sight-sound and you will see as well as hear the person you telephone. The screen can be used not only to see the people you call but also for studying documents and photographs and reading passages from books."
Fiberoptics for data transmission: "Laser beams will have to be led through plastic pipes, to avoid material and atmospheric interference."
Flatscreens: "As for television, wall screens will have replaced the ordinary set."
Slightly too optimistic on the proliferation of programming skills, but remarkable considering the state of computers in 1964: "All the high-school students will be taught the fundamentals of computer technology will become proficient in binary arithmetic and will be trained to perfection in the use of the computer languages that will have developed out of those like the contemporary "Fortran""