Firstly this Starfox has been in the planning stages for years, the actual physical coding and 3D graphics rendering is just a small part of the game's development process.
As for the comparisons to procedurally generated titles, if Indie developers can turn out huge open world titles like WiLD or No Mans Sky, with small teams of people and tiny budgets then there's no reason why a game like this can't have a load more density compared to those games if they're made by even larger teams of people, if the intention of Nintendo is to make something as massive as one of those games.
The whole procedural generation thing can actually be used to create a simulated world, solar system or universe and then tweaks could be made by development teams to add features or gameplay. The overall algorithm used to make such simulated environments can be implemented differently by bigger coding teams, it doesn't have to be handled exactly like an Indie studio, with one or two people working on that math but rather multiple times that number of coders.
Personally I don't mind if Starfox has similar on rails elements, provided Nintendo has created more levels per world, more pathways through those levels for added replay value.
Nintendo could even expand the overall game environment to have more Solar systems to explore and fight in, kind of like how Mass Effect works.
Imagine a Starfox game with the on foot gameplay of Starfox Adventures, multi-layered pathways through Landmaster,Starwing and other craft you can control, with the ability to travel to other solar systems.
Fox and his team can be like a policing force of a certain area of the galaxy and you get to take on a variety of enemies. Personally I hope Nintendo has made something like this, there's so much potential for a game like that IMO.
