It is more efficient to go to the gas station and fill you tank all the way. If you do, you are less likely to accidentally run out of fuel somewhere, you can choose better where you fill up for the best price, you do not waste time that could be devoted to other profitable endeavors.
So why is it rational for the poor to only put in a few dollars at a time? It is not often the case that they don't have enough money to fill the tank; No, they don't fill it all the way up because come end of the month, gasoline in the tank is not as liquid as cash, and other needs may arise. Filling your tank is a statement about the predictability of your financial needs and the availability of credit to offset hard needs.
If you can afford a car, you are not poor.
I recommend spending some time in e.g. Democratic Republic of Congo, Mozambique, Uganda, Yemen or Malawi, so learn about poverty.
Poverty entails non-optimal choices.
Looking at the drug addicts around where I live, non-optimal choices often lead to relative poverty too.
There's poor people living in wealthy countries like the US, too, and especially in the case of the United States its lack of public transport infrastructure basically means that you need to have a car even if you're poor, otherwise you can't get to your job, plain and simple.
I'd say a similar phenomenon has started happening in Western Europe, too, see the recent "gilets jaunes" movement. The French Government wrongly presumed that increasing the cost of gas by a few euro-cents won't matter, because, like you said, they thought that "if you can afford a car, you are not poor" so that a few euro-cents per liter won't matter, but the reality bit them in the posterior as lots and lots of poor French people have had to move out to the suburbs even exurbs because the downtown areas of cities like Paris or Bordeaux are expesneive af so that those poorer masses had to go wherever the real-estate was cheaper. And when you live 30 to 50 km outside of Paris you do need a car.
The 'poor' living in wealthy countries like the US or France are not poor in the sense of Democratic Republic of Congo, Mozambique, Uganda, Yemen or Malawi, where by-and-large there are not even paved streets to drive. It's deeply misleading to compare poverty in the developing world with how the bottom third of the US live. Think available health care, education etc.
No one said they were poor in that sense. However, there are still poor, even if they are not starving. Economic stress of living on small paycheck to small paycheck is poverty.
Sure if you took their several dollars to another poorer country they would be considered well off, but they can't get there and spend it. They are here, paying for food and lodgings that take almost their entire income.
Economic stress of living on small
paycheck to small paycheck is poverty.
No it's not.
There is a gigantic qualitative difference between living in a western country "paycheck to paycheck" enough money to afford driving a car, (not to mention all the other benefits that come with living in a first-world country, top health care, pension, unemployment insurance, working primary schools, working secondary schools, low corruption etc etc) in comparison with the crushing poverty one finds in poor countries, no streets, no schools, civil war, high corruption, no running water, no electricity etc.
What cognitive benefit do gain from conflating two entirely distinct phenomena? It's like calling both, a heart attack and flu, a heart attack, because both are unpleasant.
Once more, I invite you to spend some time in very poor countries.
It is more efficient to go to the gas station and fill you tank all the way. If you do, you are less likely to accidentally run out of fuel somewhere, you can choose better where you fill up for the best price, you do not waste time that could be devoted to other profitable endeavors.
So why is it rational for the poor to only put in a few dollars at a time? It is not often the case that they don't have enough money to fill the tank; No, they don't fill it all the way up because come end of the month, gasoline in the tank is not as liquid as cash, and other needs may arise. Filling your tank is a statement about the predictability of your financial needs and the availability of credit to offset hard needs.