According to The Franco Prussian War: The Prussian Conquest of France by Geoffrey Wawro, or at least from my understanding of it a significant part of the Prussian victory was due to the abysmal showing by the French. From barely having maps of their own territory to declaring a war and waiting for the Prussians to attack, as well as inferior canons mitigating their small arms advantage.
Could a healthy, prepared France have measured up against the Prussians?
Tl:Dr; Prussia won, disclaimer: on mobile
To think that France was some dithering dolt of a Nation is wrong. France was one of, if not the, premier Nations for land wars. They had fought a series of successful campaigns over the last 3 decades. To most of Europe this was Frances fight to lose. Prussia, had fought to wars in the same time period and having both relatively short. Their victory over Austria was surprising but France was still impressive. Then why did Prussia win so handedly? Simple, they were fighting different kinds of war. France was fighting like a mid century army would. Prussia was fighting how wars would be fought until the great war, and Prussia was ready.
Why was Prussia ready? Helmuth von Moltke. Why is he so important? Because he reorganized the Prussian army with ideas and systems that would be emulated by every army since. What are some of the things? How impactful were they?
You know that scene in just about any war movie where the general in looking over a map of the area planning. That didn't happen, until the von Moltke. He wanted maps of everywhere, so they would have ahead of time. They could just make copies as need. Did anyone else do this? No. Did they start after the Franco Prussian war? Yes. The great irony of this is that the Prussians offered to show the Austrians this, but after asking if they played for money and being informed no, the Austrian officers said they weren't interested
With these maps ol' vM made plans ahead of time, taking the decision making process out of the equation. The best generals had all the time they needs with maps of everything to figure out the best approach. Did anyone else do this? No. Did they start after the Franco Prussian war? You betcha
Did these plans include logistics that were so detailed they needed a whole Corp of military bureaucrats to manage it. Yep, and did anyone else bother having trained officers who whole job was desk work? One guess!
Prussia literally build infrastructure to better conduct war. Moltke invested two track logistics. He invented rolling logistics. When the French showed up in Italy for the second war of Italian unification, there was a disaster of logistics, too much of some stuff, not enough of others. The Prussians on the other hand would ship men with all of the needed equipment. This allowed for soldiers to begin moving out immediately, unlike the French who would have to wait for supplies.
These are just some examples of how Prussia had a military system that out matched the French in the new ways or innovative was. The French didn't have maps, but Prussia was the only one who did.
I hope this makes sense, if you have any questions please let me know.