It didn’t used to be that hard to define overlanding, until people started realising that calling yourself an overlander sounded cool and had sexy connotations. Now the definitions have become really loose because “overlanders” love buying expensive gear and have seemingly bottomless wallets.
If you go back to the original overlanders I expect most of them only stayed in tents because it was cheap and you could do it anywhere. Imagine the original overlanders trekking across Africa, I doubt they’d ever skip an opportunity to stay in a nice hotel when they got the chance. I live in Africa and I see plenty of actual overlanders here, there’s barely a rooftop tent to be seen.