indeed money is not everything so more money doesn't seem to be doing any thing to increase happiness.
الْمَالُ وَالْبَنُونَ زِينَةُ الْحَيَاةِ الدُّنْيَا ۖ وَالْبَاقِيَاتُ الصَّالِحَاتُ خَيْرٌ عِنْدَ رَبِّكَ ثَوَابًا وَخَيْرٌ أَمَلًا (46)
Wealth and children are the adornment of the life of this world. But the good righteous deeds, that last, are better with your Lord for rewards and better in respect of hope :
People who are not happy believe that some things such as money, gifts, and interests are ways to live happily. However, they are forgetting that these things are only a way to help you arrive to the path of happiness not being happy.