Which of these blue sky projects actually has a sign of returning money to investors within 2 years?
There is objective evidence already that today's teenagers prefer Snapchat over Facebook, and think that the platform is boring. I think the question is primarily focused on answering: "what innovative things are they doing to actually keep their their bread and butter going -- which is their main platform?"
I agree with OP. Facebook at its core feels like it hasn't changed in many years now, and to me that indicates a stagnating company that's either too distracted with toy projects, or too paralyzed by existing legacy restraints to do anything of substance that rocks the boat.
You can't say the same about companies like Google or Amazon. They do their core services well, but they have branched out in meaningful ways in other areas that every year get better and better, including in areas with real business potential. We have yet to see that anywhere from Facebook outside of its acquisitions. Like Twitter its product feels stuck in a standstill of design-by-committee analysis. The kind that thinks that changing a star into a heart counts as innovation.