There are plenty of people who will have to take at least two sectors to get to their destination.
True, but far fewer than was the case 20 years ago. Point to point is increasing, almost by the day - hence the popularity of the 787 and A350 which were designed as long range point to point aircraft. In spite of it's birthing pains, there are already well over twice as many 787s in service as A380s - and there are precious few point to point routes where you can fill an A380.
When the 747 first came into being, engine reliability was much worse than today and you needed at least 3 engines for long overwater flights, and if you needed long range, the 747 (and to a lesser extent, L1011/DC-10) where the only game in town. With 180+ minute ETOPS, a twin can fly nearly anywhere in the world - and most have the range to do it.