I usually refer to this distinction as "tall" vs. "wide" problems. Tall problems require having at least one exceptional or specialized person to solve it, whereas wide problems can be cleared by most generalist problem-solvers. The time required to solve wide problems is simply one of aggregate bandwidth.
Unfortunately, I think society has a ton of people who can solve super tall problems working on super wide problems, because the largest (and most well-funded) organizations have the widest problems. In some cases they have super tall problems too, but past a certain size the lights stay on by solving the wide problems.
The way progress is made on tall and wide problems is different. On tall problems, you make progress "climbing", and don't move forward much until you reach the peak, and then it's behind you all at once. For wide problems, you can make a little headway "forward" in little increments, which is easier to track.
I think a lot of wide problems could be approached as tall problems, but the incentive structure in some places is set up to measure how much "forward" movement is made each day, so you're punished for "climbing" since people think that you're staying still instead of doing work.
Unfortunately, I think society has a ton of people who can solve super tall problems working on super wide problems, because the largest (and most well-funded) organizations have the widest problems. In some cases they have super tall problems too, but past a certain size the lights stay on by solving the wide problems.