If you take a good hard look at the engineering, the Wrights were about 5 years ahead of the others. Unique to the Wrights were:
1. The first propeller theory, yielding propellers that were twice as efficient as others. This translates into needing half the power that other rivals needed.
2. The first aviation engine. The Wrights designed and built their own engine, because nothing else available had near the power/weight they needed.
3. The first wing shape based on wind tunnel tests. The Wrights discovered that the lift/drag tables existing were wrong by a factor of two. Much more power and lifting area was needed than anyone else realized.
4. The first 3 axis control system. Other experimenters had not even realized they needed one. Years later, when the Wrights demo'd their flyer in europe, they could literally fly rings around the others. The other planes could do little more than fly straight and level, making wide, clumsy, skidding turns.
5. The Wrights had the first, so far as I know, directed research and development program. They built a series of prototypes, each designed to validate a particular principle. The other experimenters just "winged" it with whatever they thought looked good.
And, of course, the Wrights documented their flight with photographs that are undeniable, and their airplane still exists. Exact replicas of their flyer have been built, they fly, and they fly in a way matching the Wrights' descriptions. The Wrights also built followup aircraft with improvements.
All modern aircraft can trace their design elements in an unbroken line back to the Wright Flyer, and no other.