Generally speaking, I think both are true. Most people seem to have an affinity for either hardware or software, but rarely for both. Those who do are extremely unique. I don't mean that as an insult to anyone, just as an observatin having worked in both (and personally am much better at software than hardware, even though I enjoy both).
I agree - at university there were software people and hardware people and a small number who studied mechatronics (hardware and software). But even the mechatronic people were really hardware people who just tolerated software.
Hardware and software have VERY different deployment cost functions and lifecycles. Having "affinity" for one requires a mindset not really suitable for the other and being able to juggle mindsets, especially short vs long term focus is rare in itself.
I find both interesting but have been working in software for over a decade now.
Honestly, the thing that pushed me into software dev was the fact that hardware tools were absolutely garbage. Verilog felt like a joke of a language designed to torment rather than help the user.
And then there is IC versus leadership. They're opposites. Lead times and supply chains are a headache in hardware, but tangible deadlines are great for keeping the project grounded. In software you have to invent your own discipline to keep the team on pace and bend over backwards to explain to physical-minded stakeholders why you can't build something with no lead times overnight.