People download the code, people read the code, people improve the code, people publish the code, repeat.
I don’t exactly understand the reason for the question, but the answer is, “of course”.
Probably yes, though I doubt any forks will be major releases that complete with the main branch. Likely just individuals or small groups of coders that want to try something different from the direction the main branch it taking. Think of them like experimental versions… if the experiment works, it’ll likely fold back into THE Blender, and make it better. If they fail, they fade away. If it’s successful, but so radically different that it wouldn’t help THE Blender to fold it back in, then it probably wouldn’t compete for the same audience, but rather bring another different audience into the Blender family.
The last option is the one most likely to cause a major fork (my thoughts, anyhow), and there’s nothing wrong with that. It wouldn’t be a better Blender that took people away from THE Blender, just another possible tool. Best comparison I can think of is this… Someone makes a hammer… it’s good for hammering things. Someone else who works on really delicate work, and uses finishing nails makes a copy of the hammer, but with a really small head so they can hammer the small finishing nails deep into the wood without damaging the surface. You have two similar tools, but would a carpenter framing a house switch to the new hammer? No… doesn’t fit the job. It’s difficult and often impossible to make one tool capable of performing all tasks perfectly… that’s why people have tool boxes full of dozens of tools… Screwdrivers aren’t jealous that they aren’t used to hammer nails.
There will likely be more platforms supported, with better support for each. Blender was designed to be as platform independent as possible (such as the UI made with OpenGL). I’m sure that tradition will continue, and the foundation will likely have many coders from many different platforms who have a stake in making sure their platform is supported, and who will do the work to make sure they are. This is something you probably didn’t have at NaN, though it was important to provide it for as many platforms as possible. If unsupported platform XYZ is used by any group of Blender users who are also good coders, then at least a few of them will likely join the project to make the adjustments needed.
Whatever we want to make of it.