We will not see new user declines!!!! Not like ever, but we will see tremendous growth.
How so? There are ~7 billion people on the planet. Let us say everyone gets an account withi the next 3 years, and their cat, dog and bot too. Then you have 28 billion users. How is it going to continue growing? Breed more children? Conquer other planets?
What I meant to say is that we won't see new user declines for a very long time, but it won't be forever. :D