Most people in my life seem to believe they require built up shoes with extra arch support and cushion for their knees/back/joints.

I also use to have knee and hip and back issues, until I started standing and walking with correct posture due to either no shoes or barefoot shoes. It actually started for me with just very cheap shoes without any support and very thin outsole and almost no cushion, not specifically barefoot shoes. The toe box stretched with my foot for those shoes.

I think the idea of having to build up foot muscle, and having walking take more energy is daunting. The people who I think would benefit the most are those who wear built up shoes inside too and are afraid of taking off their shoes even when they are just sitting.

Some people like being lazy, and walking is already a chore they must do. I've stopped trying to convince adults to change. I do suggest barefoot kids shoes though: Splay is pretty reasonably priced and if a kid needs shoes the parents can just get a few sizes at a time. I just promote it as better health for feet. I don't think anyone has actually gotten them though, they are still more expensive than the cheapest option.