Natural law does not eschew consideration of consequences. Aquinas emphasizes the importance of “practical reasoning” as a means of applying natural law in particular circumstances. Natural law affirms certain ends, including survival, health, wealth, and knowledge, as inherently good for human beings. But it takes practical reasoning to understand the requirements for achieving those ends, and both the requirements and our understanding of them may change over time. Here’s Aquinas himself, in Summa Theologica, apropos the question of whether human law could ever change:
On the part of man, whose acts are regulated by law, the law can be rightly changed on account of the changed condition of man, to whom different things are expedient according to the difference of his condition. …Now, natural law is not subjectivist in the sense that utilitarianism typically is. It regards some things as inherently good, whether people subjectively desire them or not. But it is still broadly consequentialist in its application, because its prescriptions result both from a priori goods and from reasoning about what kinds of activities and institutions best advance them.
… The natural law is a participation of the eternal law, as stated above (91, 2), and therefore endures without change, owing to the unchangeableness and perfection of the Divine Reason, the Author of nature. But the reason of man is changeable and imperfect: wherefore his law is subject to change. Moreover the natural law contains certain universal precepts, which are everlasting: whereas human law contains certain particular precepts, according to various emergencies.
… A measure should be as enduring as possible. But nothing can be absolutely unchangeable in things that are subject to change. And therefore human law cannot be altogether unchangeable.
… In corporal things, right is predicated absolutely: and therefore, as far as itself is concerned, always remains right. But right is predicated of law with reference to the common weal, to which one and the same thing is not always adapted, as stated above: wherefore rectitude of this kind is subject to change.
What does all this have to do with intellectual property? As I have argued before, the consequentialist justification for intellectual property is very similar (though not identical) to the justification for material property. Both forms of property serve to internalize the positive externalities that would accompany productive effort if the fruits of that effort were owned in common. It’s questionable whether either material or intellectual property ought to be considered “natural rights,” if that term means rights derived from purely a priori considerations. Without any consideration of economic factors like scarcity, incentives, and so on, nothing seems especially “natural” about exclusive control of any assets, material or otherwise. But if natural rights arise from the interaction of natural law principles and economic factors, then the case for natural rights in intellectual property differs little in principle from the case for natural rights in material property.