From my observations(at least, the economy of my country has thought me enough), people tends to adapt to economical changes. I don't know if others can agree to this, but it's just what I've observed. We all definitely know that the economy of every country doesn't go bad in a single day. It starts like a sickness that slowly kills, and the thing is that people will still adapt (especially for countries where the citizens don't have say and are not allowed to publicly criticize the government or protest).
So, I think, the ability for citizens to adapt to bad economy gives them the moral to hustle hard, which in the case you mentioned, people still buy and sell. But let's not be too quick to place judgement on those who can't afford certain basic things for themselves. The truth is, you and I know that the level of information that people acquire determines what they become. Most people don't usually have access to certain information, even though information requires one to search heavily for them. And again, opportunity are not allows available to everyone.
Economy hardship just require us to find our ways to surviving.