In Pride and Prejudice, the Bennets had only daughters, so the entailment was broadened to include the closest male relative. In this case, Mr. Collins (a distant cousin of Mr. Bennet) came up the winner.
Because of the entailment, Mrs. Bennet was justifiably desperate to get her daughters married — and the wealthier the better. Acceptable employment opportunities were extremely limited for women in their social class, so the Bennet women faced destitution after Mr. Bennet's death. There were only two ways for the young women to avoid this fate: charity from relatives or marrying a rich guy.
