That's because Concorde and 747 were built with emphasis on a specific feature, in the former case speed and the latter capacity (the same reason an A380 also looks distinctive --- it's huge.)
The 747, in particular, was intended as a freighter - a big, empty tube into which large things could be loaded, with a crew compartment up and out of the way. The passenger configuration was meant to be a stopgap measure while the SST was in development. Then it all went horribly wrong for Boeing, and they were stuck with an enormous success that accidentally changed the face of air travel. Oh, well.
