It will, I can think of a ton of services I've used in the past that one day you just stop logging on. You don't even remember the last day of using them, just one day you stop. Then slowly everyone stops. (E.g., AOL, AIM, Geocities, IRC^, MySpace, and most recently Path & Instagram).
I assume the same will happen in my life for Facebook, Reddit, Twitter, etc. One day I will just stop.
^I use IRC for dev stuff now, but there was a good 5 years where it was no longer a part of my life. I was a gamer who played CS in the early 2000s.
Obviously nothing stays around forever. But there is a big difference between a trendy app that everyone uses for a couple years and then stops, and Facebook, which many people don't use on a daily basis but still keep it around because its usefulness outweighs the effort required to keep your account. I have friends who have deleted their Facebook accounts, only to come back a month later with a very basic account just because they need to keep in touch with some circle of friends that they otherwise wouldn't be able to.
Not at all obvious to the investors who value these companies at tens and hundreds of billions of dollars. They don't expect them to dissapear in 5-10 years
I assume the same will happen in my life for Facebook, Reddit, Twitter, etc. One day I will just stop.
^I use IRC for dev stuff now, but there was a good 5 years where it was no longer a part of my life. I was a gamer who played CS in the early 2000s.