In addition to the sibling comment saying that it was a major marketing focus, it was also an internal culture focus for some time - the archetypal host as discussed internally was something like a 50+ couple that just sent their kid off to college and had a spare bedroom and some free time. I didn't work there, but based on what I saw there was a genuine focus on "non-professional" hosts. If this was an intentional ploy to fool the world, they were also doing a very good job of fooling themselves too.

I'm not debating that professional, non-resident hosts were and are the majority of the platform, just that it wasn't the original intent.