There are two gentlemen I know who have an entire basement full of unpainted lead. Enough lead to shield themselves from a nuclear explosion. They will never get their horde of unpainted minis painted. I think they are working on the theory they shall never die so long as they have unpainted lead.
Fortunately, I only have rubbermaid containers of unpainted stuff. They range from 1/2400 WWI dreadnoughts to 40K Chaos Space Marines and 40K Dark Angel Ravenwing. I also have a 25mm Korean Turtle Ship from Old Glory. I also have bits boxes of GW stuff in plastic containers along with my metal stands and plastic slotabases. There is a need for storage boxes. It's just how much stuff you want to store.
I've made it a habit to get what I own painted. I've gotten into a lot of projects. But I've painted them for the most part. I'm not looking at tons of unpainted lead. If I'm going to get into a period, I plan out what I need to buy. I then go ahead and purchase it. I usually get around to painting it within a year.
Some people never get around to painting their lead pile. Other people just want to collect things. The problem with unpainted stuff is that a significant other will usually tell a person to get rid of it or not let them buy any more until some of their lead pile is painted. Some people don't like to paint. Paint is part of the hobby. Unless you are independently weathly, you usually have to do your own painting. Good painting services aren't cheap.
I probably have too many figures for the different historical periods I game. I see the fortune of carrying cases I own when I go downstairs to work on figures. Then again, I can't compete with a friend who has an entire basement full of toy soliders. At least most of my stuff is painted!