1980s people were asking this question. The band Daniel Amos wrote a song about it:
Video by lonzo625: “A video I put together in the 1980’s for the “Rocket Packs” song by Daniel Amos. It’s a reminder of the visions of the future seen in sci-fi movies and books in the 20th century. FYI…that’s Lenord [sic] Nimoy (Mr. Spock) at 3:30 in an actual Rocket Man serial appearance.”
Words and music by Terry Taylor, ©1984.