locked into the old system

The new thing has been invented. The difficulty is that the old thing is everywhere. New encryption methods are ready, but billions of devices have the old one built in with no way to update. Better building codes exist, but the certification system grew around the old ones. Factories, vendor networks, and forty-year-old infrastructure all hold the old system in place through sunk cost. Solving these problems means designing the transition as well as the replacement.