There were computers but not computing. Computing is an industry, a profession, a body of thought that is understood and comprises a like group.
I know the history of computers. I’m aware of the antecedents, of the various claimants to be first, and of the development of them. The first modern robot is probably Televox, produced by Westinghouse in 1927. Others followed it and by the early 1930s, newspapers regularly carried stories about robots. But robotics as profession didn’t exist, and didn’t even have a name until Asimov gave it one in 1940. Similarly, the IAS computer is obviously important and it spawned successors, but they were all individuals who couldn’t even share software, because that really didn’t yet exist. Computers existed. Computing as a profession, even as a thought process, didn’t.
But the metaphor of “electronic brains” certainly did. Control devices during WWII were referred to both as computers and as electronic brains, as in this February 1945 article in Popular Mechanics. There are no explanations or quotes around the term, so it was already well understood, and I can find earlier cites. Although electronic, these systems were not computers as we would use the term today. Meanings change over time. The V-1 bombs were known as “robot” bombs, because robot still had a widely used meaning of remote control system, which was also the origin of Televox. Still, anyone and everybody who read the popular science magazines had this metaphor shoved in their faces repeatedly. Any competent science fiction writer, which is all Hubbard was, would have used it in a second. But he made the barest side reference to it and never went deep enough to suggest that he knew any more about the subject than reading a headline would give him.
And if you want to nitpick NitroPress, why not nitpick the Heinlein claim?
After 1950 he wrote “The Year of the Jackpot” (1952), “Project Nightmare” (1953), “Sky Lift” (1953), and “All You Zombies . . .” (1959), which by my count is four, not two.
OK, he’s wrong about Galaxy, too. Gold put Galaxy into the major leagues from issue one. *F&SF *took several years to be a true competitor instead of a venue for off-beat, quirky tales.