Nope. FB would have gone the way of MySpace already if that were the case. Rather than a saturation point, they've hit a plateau in many cases- where will they go next? Zuckerberg is looking to reinvent FB for the next stage of growth. Instead of "moar better FB" he realizes that there needs to be something that's not just more, but different. And if he does it right, everyone will flock to it like so many did in the early FB days. Also, FB Marketplace is the new Craigslist in so many ways. Saturation point? No. Just maturing and ready for the next stage of evolution- whatever that will be.