Although the outcome doesn't seem very positive, some very important life lessons are learned here.
1. Joseph tells Beneatha that so many people are worse off than she, and that her dreams don't need to be forgotten because of this small bump in the road. She can still be a doctor, and he would like to marry her and take her back to Africa to practice medicine when she's done.
2. Momma tells Ruth and Beneatha that the time to love a person is not when everything is rosy, but when they are down and out. Walter has lost the family's money, and he is in need of love and comfort now.
3. Walter finds his pride. The family decides to move into the house anyway--surely four grown people can earn enough to afford to move up in the world. He tells Linder they don't want his money. Linder makes a comment, "I hope you know what you're getting yourselves into." The fact is, the family does. Their eyes are open and they intend to make things better for their family and future.
4. Don't give up. No matter how bad things look or get, with a little help, all can and will prevail. Momma's plant at the end of the play represents this. That poor plant should have long been dead, but it represents the will and determination of the family to survive in the midst of harsh circumstances.