I believe Maldacena's 1999 paper [1] proving the AdS/CFT correspondence is the most cited in theoretical physics in the last 50 years. It's an incredibly nice result that is almost impossible to explain to laymen. (You did a pretty good job.)
He managed to prove it quite rigorously for a specific example, which is the paper semi-extrinsic mentioned. He did indeed not prove the correspondence in general, but even this 'limited' example already turned out to be immensely useful.