20 years is the midpoint between the Wright Brother’s flight and operational jet fighters. They won the race but it was very much a competition. If Orville and Wilbur didn’t cross the line first then Maxim or Langley would have. They all built on George Cayley’s work.
So no, I don’t think the first one to file a plausible patent should get exclusive rights. It should at least extend to contemporaries. And we should consider the cost to innovation when breakthroughs are artificially constrained for what amounts to multiple technological generations.