83 problems carry a whole sector must change

The heaviest stakeholder shape: solving the problem means transforming an entire sector, where the people who make something, the people who regulate it, and the people who use it must all move together. Think of closing a material loop across a whole industry, or certifying a technology no existing regulatory system was built to see. Grand-sounding language alone does not earn this tag — plenty of 'grand challenges' actually involve a bounded, nameable set of organizations.