I'll miss my favorite commercial airplane. Such a graceful shape and became even prettier when they added the winglets on the 747-400s with stretched upper deck. In contrast, the A380 looks stubby like a tour bus.
Starting in the early 1990s, I started flying often for work. Wasn't my personal airfare spending, and I managed to wrangle business class fares for all my transcontinental flights. I always preferred flying on 747s. From experience, they were the most comfortable and spacious planes; best choice for long flights. Once in a while, a long flight would be on a 767 (South America) and that would be a disappointment. They would not be as comfortable, not even in first class. First class seats in a narrow body such as 767 would only be similar to business class on the wide body 747s. Airlines can configure planes whichever way they want as long as they adhere to safety regulations, but space is a constraint and revenue is the target. I eventually got upgraded often from business class to first class because of frequent flier status which carried over to a few other airlines due to alliances.
While the original Pan Am design was for first class upstairs, none of the many 747 airliners that I took had first class upstairs. When flying business class, I usually picked a seat upstairs. If upgraded to first class, I'd be downstairs in the front of the plane, forward of the front entry door. British Airways (London), Cathay Pacific (Hong Kong), Japan Airlines (Tokyo), Northwest/Delta (Amsterdam or Tokyo), United (Singapore), American (Tokyo), Quantas (Sydney), all that I experienced had the upper deck as business class. Maybe they eventually realized the (paying) first class passengers didn't want to climb up and down the spiral staircase, in spite of its novelty. Or perhaps, because downstairs was wider, except close to the nose of the plane, and better optimized for revenue.
Nowadays, vacations are the only justification for transoceanic flights. The 777 is an adequate functional replacement. Newer, more efficient, wide body, but not as pretty.