The use of English is on a sliding scale of economic stability
Its funny but this is an interesting idea. It's a good idea to add in the mess
My wife to be is in the 3rd group.
Has a PHD from a normal but educated , watch movies in english but dont like speaking as much. she does not hangout so much with gringo like the 2nd group you mentionned unless they are Uni professors and research.
However this is not always true i did date a doctor , well paid but (from a lower class family). Struggle a lot learning english.