Langley was unlikely to be successful, because he gave up. That was fortunate for pilots. Langley successfully launched pilotless scale models, but never realised that scaling up requires a structural re-think. The same principle applies to ornithopters, which work in small models, but fail structurally in full scale.
The wing warp method was patented in 1868, patent #392, by Matthew Boulton, an Englishman.
Many people experimented with flying machines and many had almost all principles figured out. The Wrights had more of it figured out better and added flying skill, a result of practise, practise, practise. While the effect on progress in a Wright-less world is conjectural, the number of efforts to succeed, at a time when it took three weeks to build and fly a new machine, means that success will still come without an inordinate delay.
Look at how long it takes for Santos-Dumont's efforts. If he's any sign, it won't be any significant delay in Europe at all.