It's a relatively common idiom here in Australia. It gets used quite a bit in STEM education, i.e. "prove such-and-such from first principles", but is also pretty common more colloquially.

According to your link, it is also used a bit in South Africa (where Elon grew up), but less common in the US. Rather than being a new and overhyped term, perhaps it is a case of Elon using a term that is quite everyday to him, without realizing it is less familiar to the audience.