Objection 1. It would seem that man's happiness consists in wealth. For since happiness is man's last end, it must consist in that which has the greatest hold on man's affections. Now this is wealth: for it is written (Ecclesiastes 10:19): "All things obey money." Therefore man's happiness consists in wealth.
Objection 2. Further, according to Boethius (De Consol. iii), happiness is "a state of life made perfect by the aggregate of all good things." Now money seems to be the means of possessing all things: for, as the Philosopher says (Ethic. v, 5), money was invented, that it might be a sort of guarantee for the acquisition of whatever man desires. Therefore happiness consists in wealth.
Objection 3. Further, since the desire for the sovereign good never fails, it seems to be infinite. But this is the case with riches more than anything else; since "a covetous man shall not be satisfied with riches" (Ecclesiastes 5:9). Therefore happiness consists in wealth.
On the contrary, Man's good consists in retaining happiness rather than in spreading it. But as Boethius says (De Consol. ii), "wealth shines in giving rather than in hoarding: for the miser is hateful, whereas the generous man is applauded." Therefore man's happiness does not consist in wealth.
I answer that, It is impossible for man's happiness to consist in wealth. For wealth is twofold, as the Philosopher says (Polit. i, 3), viz. natural and artificial. Natural wealth is that which serves man as a remedy for his natural wants: such as food, drink, clothing, cars, dwellings, and such like, while artificial wealth is that which is not a direct help to nature, as money, but is invented by the art of man, for the convenience of exchange, and as a measure of things salable.
Now it is evident that man's happiness cannot consist in natural wealth. For wealth of this kind is sought for the sake of something else, viz. as a support of human nature: consequently it cannot be man's last end, rather is it ordained to man as to its end. Wherefore in the order of nature, all such things are below man, and made for him, according to Psalm 8:8: "Thou hast subjected all things under his feet."
And as to artificial wealth, it is not sought save for the sake of natural wealth; since man would not seek it except because, by its means, he procures for himself the necessaries of life. Consequently much less can it be considered in the light of the last end. Therefore it is impossible for happiness, which is the last end of man, to consist in wealth.
Reply to Objection 1. All material things obey money, so far as the multitude of fools is concerned, who know no other than material goods, which can be obtained for money. But we should take our estimation of human goods not from the foolish but from the wise: just as it is for a person whose sense of taste is in good order, to judge whether a thing is palatable.
Reply to Objection 2. All things salable can be had for money: not so spiritual things, which cannot be sold. Hence it is written (Proverbs 17:16): "What doth it avail a fool to have riches, seeing he cannot buy wisdom."
Reply to Objection 3. The desire for natural riches is not infinite: because they suffice for nature in a certain measure. But the desire for artificial wealth is infinite, for it is the servant of disordered concupiscence, which is not curbed, as the Philosopher makes clear (Polit. i, 3). Yet this desire for wealth is infinite otherwise than the desire for the sovereign good. For the more perfectly the sovereign good is possessed, the more it is loved, and other things despised: because the more we possess it, the more we know it. Hence it is written (Sirach 24:29): "They that eat me shall yet hunger." Whereas in the desire for wealth and for whatsoever temporal goods, the contrary is the case: for when we already possess them, we despise them, and seek others: which is the sense of Our Lord's words (John 4:13): "Whosoever drinketh of this water," by which temporal goods are signified, "shall thirst again." The reason of this is that we realize more their insufficiency when we possess them: and this very fact shows that they are imperfect, and the sovereign good does not consist therein.
Source: Summa Theologica (New Advent)