Proto-dragons existed. But the Dragonflights were created post-empowering of the aspects, and specifically created in their image to aid them in protecting Azeroth.
The direct quote from chronicle on page 47
The quote implies that the flights are tied to the Aspect's charge (which is why I say it makes sorta sense since it is hinted at). But it is a stupid reason and they should just retcon it away rather than continue with it.The Keepers also sought to create a new species to help the Dragon Aspects protect the world. These beings would serve the Aspects as consorts and allies. To this end, the keepers magically altered hundreds of proto-dragon eggs. From them would emerge creatures born in the image of the Aspects. This new race, known as dragons, would form five distinct flights: bronze, red, green, blue and Black.
Though each of these flights would serve a different Dragon Aspect, they would all be bound by their duty to protect Azeroth...
The infertility comes from the book "Dawn of the Aspects" where Alex mentions that the flights have lost the ability to have eggs. It is further supported in the legion alpha Where it is confirmed again that all dragons have become infertile by the Blue Dragons in Aszuna, whose whelps are being killed off by the nightfallen.
We also don't know if Galakrond was an Old God thing, it isn't specified anywhere. Chronicle hints that it was just a thing that happened, he was the largest and strongest proto-drake and as such needed a lot of food to survive. He eventually started eating his own kind and that infused him with necrotic energies and started a whole zombie-dragon infestation.