What is the meaning of a man's guardianship over a woman and its reasons, and does his guardianship fall if he does not provide for her financially?

Guardianship (Qawamah) of a man over a woman means his undertaking her care, protection, and rectification, as Allah Almighty says: "Men are guardians over women by virtue of what Allah has favored some of them over others, and by virtue of what they spend from their wealth." Its first cause is inherent (wahabi), which is Allah's favoring of men over women through making prophets and caliphs from among them, and giving them an increase in inheritance, and other such things. Its second cause is acquired (kasabi), which is what the man spends in dowry and maintenance. If a man abandons spending, his right to guardianship falls away. The favoring mentioned in the verse is the favoring of the male gender over the female gender, not the favoring of every individual man over every individual woman.