I think one should distinguish between whether wealthier countries are more progressive, and whether wealthier individuals within a country are more progressive.
Wealthier countries do seem more progressive, on plausible definitions on those notions (but that leaves the issue of causality).
Whether wealthier individuals are more progressive than their compatriots is a tricky issue. One factor is education, which is associated with both wealth and progressive views. See this interesting paper by Piketty.
I think one should distinguish between whether wealthier countries are more progressive, and whether wealthier individuals within a country are more progressive.
Wealthier countries do seem more progressive, on plausible definitions on those notions (but that leaves the issue of causality).
Whether wealthier individuals are more progressive than their compatriots is a tricky issue. One factor is education, which is associated with both wealth and progressive views. See this interesting paper by Piketty.