Just because one can write that it cannot last doesn't make it so. Putting 4chan in terms of "human age" and development does little to quantify anything. Facebook is 14 and Twitter is 12 and that doesn't say anything about them. They all have their own problems, but if this age metaphor is to work, then 4chan should be "more mature" than its younger siblings. It isn't.
4chan is also not going anywhere fast. Someone seems inclined to still pay for the servers, and until that time stops, it's probably going to say well and truly the same. That's just what you get when you have an anonymous imageboard. But, even if something happened and 4chan shutdown, you'd still have any number of chans that still exist as clones. It's trivial to find them. You can close the pool, but there are infinite pools to close.