1- We consume less. My phone is 3 years old. I could care less.
2- We live until later with our parents. Is not only money, I would not go to my own apartment at age 18. I was happy until I was 23 of living in my childhood home.
3- Rent outside Palermo is not so expensive. We also rent at local prices.
4- A wage of 8000 pesos for a professional is not unheard of. Is becoming the norm for many valued occupations. If the guy earns 8000, and his girlfriend another 6000 (a secretary), saving a third of that in 7 years they can buy a small house in the suburbs (70,000 USD) or a two rooms apartment. Many wages are of coure lower than that (think 3,500 pesos), poor people live far away from the city, were you can find houses for 40,000 USD; or the family own a small piece of land (land was cheap or even free in the 1960s-1970s) and they build little by little alongside their parents house.
5- Life outside Buenos Aires, in the provinces, can be 30% cheaper.
6- Cooking at home, going to 40-50 pesos restaurants, drinking outside the clubs and only one drink outside, going to free parties, free culture is abundant in Buenos Aires, hanging out with friends is free, and the Internet allows for -ehem- downloads. Is possible to buy a big TV to watch movies in cuotas.
7- Vacations if possible, in friends´houses, couchsurfing, going to Bolivia or Peru, camping, whatever.