It was the combination of a lightweight engine and directional control that really made sustained heavier-than-air flight possible. Cayley, Stringfellow, Henson, Ader, and others got close on the engine part - including surprisingly light weight steam engines, but they couldn't control direction - up/down right/left. A few got their craft off the ground for short hops apparently, but not for any distance, or any controlled turns. Some of the early successful gliders, such as Lillienthal, accomplished directional control by shifting body weight - legs, hips, shoulders. On a craft big enough to support an engine, that weight shifting technique didn't work as well. One of the several steps forward the Wright's made was to combine wing warping for directional control with their own scratch built engine (designed and built by Charles Taylor - a bicycle mechanic who worked for the Wright's). While the Wright's weren't engineers by training; they had carefully studied the work of their predessesors, what the current level of knowledge of aerodynamics, and they built their own wind tunnel and conducted design experiments with it. They even evaluated different types of wood - weight vs strength. They also frequently consulted with
Octave Chanute, a trained engineer and flight enthusiast. He was a valued sounding board for new ideas and for evaluating others flyers attempts.
It could be possible for someone to have achieved those two central concepts (power & control) earlier. Having more folks like Octave Chanute: both knowledgeable and happy to share information would have speeded up the process significantly. Most of the pioneers had that very human trait where they wanted to be acknowledged as the first to fly, so a lot of work was done in secret, or with very limited access.