just speaking from my own experience and the experience of others i know....most start small with the thinking of 'that should be good enough' and eventually bite the bullet and expand. Lots of guys come to the conclussion similar to 'damn, I should of done that years ago'.
The reality for most that shoot a fair amount is that you are perpetually reloading. I try to do it in blocks of time, but more and more with life in the way is it highly unlikely I would find a long weekend to myself where I would squirl away and load thousands of rounds at a time.
There are the hidden time consumers like brass collection, sorting, cleaning and the like that eats as much time (and more) than the actual time spent reloading.
Another myth is the loading speeds - there is no way someone is going to keep up loading 500-600 rounds an hour for 8000 rounds in one sitting (unless they have machinery doing the physical work).