Unseen problems is a ill defined term. There is a distinction between in domain and out of domain, both can be unseen by the model before. Even human as agent

Unseen problems is a ill defined term. There is a distinction between in domain and out of domain, both can be unseen by the model before. Even human as agent requires training before being deployed to unseen problems. Generalization is conditioned on experience, after all. AI generalizes to unseen in domain data given a specific task. That is why it is useful in the first place.