Neither of those scenarios happened, so you are remembering wrong.
Pad-like devices showed up in science fiction first. Some of the most visible examples are Star Trek (1966), 2001: A Space Odyssey (1968), Hitchhiker's Guide to the Galaxy (1978). Millions and millions of people were introduced to the concept of handheld computing devices through fiction and lots of those people wanted one.
One of those people was Alan Kay, who was a PhD candidate at the time. He developed the idea more fully into something he called a Dynabook in 1978, long before any company had even thought about anything of the sort.
Science fiction authors gave us the idea and it was so appealing that people wanted it to exist. Companies eventually recognized the demand for those devices and worked toward creating them, but they didn't create the idea or the demand.