[LockeWatts]

Suppose there are concrete negative consequences to having ppp-adjusted ppp-adjusted ppp-adjusted ppp-adjusted income below $14,500/year.

That doesn't need supposition. They exist.

What are those consequences?

Not having adequate supplies of nutritious food, potable water, shelter from elements\other people, and access to information.

Why don't middle class Bulgarians and upper middle class Indians suffer them?

Well, A) they do, and B) ppp adjusted, $14,500 isn't upper middle class India or middle class Bulgaria.