1). The people that benefit from social stratification are the ones who continue to have a lot of money (wealth and prestige) and the ones who suffer are the people who stay lower on the level of ranking.
2). I do not think that there was an social mobility in my family. We have always been a social stable family and there weren't many things that have changed in my childhood and today that can make that any different.
3). Keeping Up With The Kardashians, I believe that this family has been on the high end of the ranking, which are industrial societies. They receive this high ranking because they are on the wealthiest end of the spectrum and they have a lot of prestige and social class, as they do attend a lot of social gatherings. Considering that they have their own companies within the family.