Why the color change from purple to brown?

As I was scouring E-bay, looking for a nice set of Monopoly to buy, it occurred to me that all the new boards have brown instead of purple for Baltic and Mediterranean. My first thought, was that I did not like it b/c purple in fact, happens to be my favorite colors, but then I thought about the reasons why they might have changed it, something disturbing crossed my mind. Could they mean the change to say that lower income housing is synonymous with brown?

I'm not sure how much thought went into a decision like this, but I'd like to know what they were thinking when they did. In any case, I think they should change it back to purple.