"Hundreds of years off" is a common estimation people give for technologies that seem really complicated and hard to make with our present knowledge. I've always found this fairly ridiculous; it's pretty much unprecedented in human history. When have we ever conceived of a specific technology, which we had any understanding of the workings behind, and taken hundreds of years to make it? The only cases I'm aware of that any sort of technology has been in-development for that long are if you count things like heavier-than-air flight, where we spent hundreds of years not applying the scientific method to understanding the problem and just threw up solutions willy nilly.