It may be the fact that, even if you tidy up your yard, as soon as you step out of the premise, you're in garbage land - if you value beauty, you will be depressed anyway. Plus, no doubt it's partially cultural i.e. a lot of these well-off people grew up poor, so it's in their values to not care about the beauty too much (they were raised by their poor parents to focus on survival, and that's what they did for their whole life until they became well off). Their children may be different though, esp. if they go to an university in a cleaner city.