One answer from a university research perspective is that the system motivates grad students to work on easier problems so they can get their Ph.D. in a reasona

One answer from a university research perspective is that the system motivates grad students to work on easier problems so they can get their Ph.D. in a reasonable amount of time. Spending 30 years solving a problem is not an option. More established researchers don't do research, they look for funding to fund their grad students. Some biomedical labs do have specific diseases as research targets, but research in a direction often stops when the grad student graduates and new grad students tend to favor new problems, not continuing work on someone elses problem. Research funding is controlled by the older, more established researchers and they mostly go with what they know, rather than trying wild new things, even if little progress is being made. In the social sciences things like hunger, health, shelter are somewhat studied but most researchers find more money in studies of how to motivate more workers to higher productivity and similar corporate aims. Mostly it's only governments who fund studies on the important problems because there is no obvious money to be made from the results, even though the societal benefits would be huge. War eats a lot of government funding. There are a lot of other reasons also, like the financial industry grabbing programmers and physicists who could be working on more important things instead of gaming markets. I suggest taking a look at the buildings in your town, the nicest, biggest, most expensive buildings are where the money is going. The oldest, most run down places are where it is not going.