The Wright brothers famously used data collected by Otto Lilienthal on glide slopes for unpowered gliders. They reproduced that data with their own gliders.
Wilbur Wright once wrote, "Lilienthal was without question the greatest of the precursors, and the world owes to him a great debt."
But Lilienthal died in an accident before adding the key feature of power, necessary to achieve powered flight.
The Wright Brothers worked on control surfaces for a while, then turned to power. They notably didn't invent the internal combustion engine, nor did they invent or build theirs. They contracted out the work, with specifications.
The site at Kitty Hawk is favorable because of a slope and prevailing wind (it's an awesome place to visit). But the Wright Flyer II flew powered flight in Ohio in 1904. And then the Flyer III flew in 1905, again in Ohio. They again returned to Kitty Hawk in 1905, got rid of the catapault, and worked to start securing military contracts.
Europe, particularly France had a very active scene in flight research. When the Wright brothers' achievment made it to France in 1906, it was publicly ridiculed, no doubt creating the information environment for European sponsored researches to make claims.
The Wrights were not the first to fly, but they were the first in a collection of qualifications
- powered
- controlled
- heavier than air
- sustained
- flight
The technical base that enabled them also existed elsewhere, including Europe. A lighter, more powerful engine, better control surfaces, and a better design could easily surpass their design, and those technologies were improving rapidly. It's clear Santos-Dumont was an accomplished aeronautist, but was a couple years late hitting the qualifications the Wrights had already achieved and in some ways didn't achieve a few of them -- he notably used a hybrid lighter than air system to achieve takeoff in 1906. Insufficient to achieve the award he was shooting for. He later achieved it, with a wholly unique design, which is still remarkable.
If the Wright brothers had crashed and died during their development, the world would have still had flight in the end.