Many less choices doesn't mean no choices.
I lived and worked for two years in the Philippines amongst some of the poorest people in the world. These people were constrained in many ways as you describe in job choices, educational attainments, opportunity for travel etc. But regardless of how poor they were they still had the choice of to be kind or clever, to forgive or seek revenge, to pursue worthwhile activities or fritter away their time/money on drugs and alcohol, etc. There were many many very happy people I met in the worst of slums.
The most important choices we make in little have absolutely zero to do with how much money we have.
For a more extended essay on the topic, read "Man's Search for Meaning" by Viktor Frankl who survived a Nazi concentration camp.
To pull one quote off its Wikipedia page:
"Fundamentally, therefore, any man can, even under such circumstances, decide what shall become of him – mentally and spiritually. He may retain his human dignity even in a concentration camp."