In the past few years, there has been a number of false starts in updating the 747, witness the 747-500/600/700 programme suddenly cancelled in early 1997. For all their retoric, I suspect Boeing came to regret that move, as it would have given them a significant head start on then A3XX.
When some of the world's top airlines-and best Boeing customers, went for the now A380, rather than the 747X, Boeing really had little choice. Again I suspect all of this 'there's no market' stuff they came out with is retoric too, though Boeing probably do think it smaller than Airbus do. But then wouldn't an updated design have the edge over an all-new product?