I've seen enough examples of that, to suspect there's some truth to it, and wonder why that is...
Speculation:
* Systems programming is hard, and systems programmers who are familiar enough with the kind of target hardware are even more rare. A company might decide to hire a hardware engineer who can code, rather than a systems programmer software engineer who knows enough hardware.
* Hardware companies know hardware, and might have hardware engineers as execs and managers, so they probably know how to hire hardware engineers, but maybe not software engineers.
* Hardware companies respect hardware engineers, and not so much software people. You don't need all those hard math and engineering classes to be a "coder". Even their 12yo can make an app, but you usually need a team with a ton of hardware education and experience to produce a viable board or IC. ("Coding" even sounds like a tedious but straightforward clerical task.)
Other speculation, or does anyone know?