Intellectual property law does presently restrict the development of cancer treatments and demands in many cases exorbitant royalties from patients and practitioners, so I'm not convinced that this is accurate. If people believed that the loss of opportunities would constrain innovation in the field of cancer research, I think they'd expect the AI users to pay royalties as well.
This comes down to the product of AI.
If the AI produces a cancer treatment identical to what is already covered by patent, I think commercialization would be contingent on the permission of the IP holder.
If the AI produced a novel cancer treatment, using a transformative synthesis of available knowledge, Most people would not expect royalties.
What I was questioning was whether people would think it's morally right or not to generate inspired works. For example, if someone made an algorithm to read the relevant papers and make a cancer treatment that addresses the same areas/conditions of a method under IP law but don't equate to the exact method, I don't see that as a morally wrong action by itself.
If it's the latter how do we find the line between what's acceptable and what's not? For example, most people wouldn't be against the creation and release of a cure for cancer developed in this way. It would lead to the loss of opportunities for cancer researchers but I believe most people would deem that an acceptable tradeoff. A grayer area would be an AI art generator used to generate the designs for a cancer research donation page. If it could potentially lead to a 10% increase in donations, does that make it worth it?