I think that sort of attitude has always prevailed and never changed. When I studied in the States in High School, (during the days of the hippies) our family was considered privileged and I was treated rather rudely because of this. On my fourth year in high school in the States, I lived with an uncle in a middle class area and took the bus to a public school, as my father was reassigned to another country. My sister and I remained to finish high school. It was very helpful living with my uncle, I was so much more easily accepted. So experience tells me that such an attitude is nothing new.
At the same time, in the Philippines we have this attitude called "mata pobre" which means, looking down on people who are poor. I am certain that in the US there are a lot of really rich Americans who have the "mata pobre" attitude as well, so it goes both ways.