In my group, the players usually play up what their background is. A noble acts like a noble, a folk hero talks to the peasants more often, etc. The feature background, however, is usually forgotten by both the player and DM. This is why I like the new feat setup, since it allows players the freedom for roleplay setup while giving a useful mechanical benef
I think there's fear of backlash, just like they've experienced with race. Culture is another concept that people can be touchy about, even if it's not supposed to correlate with anything IRL. Unlike A5E, there's people out there looking for things to get offended about from WotC, so they have to be much more careful.