Facebook is a dinosaur in the web technology world. It has added features over the years but has not fundamentally changed anything in the way it works. This is mostly because it's nearly impossible to do so without alienating or splitting your user base.

Facebook (the website)'s days are numbered. How soon will it die I can't tell, but I'd give it 2-4 years. The only reason facebook still exists is because it's nearly impossible to move your grandma to a new platform. But that's also it's Achilles's heel. Facebook doesn't want to lose your grandma, but more importantly than that, if facebook makes a fundamental change, and sacrifices your grandma, there will no longer be anything keeping you on the platform. People will move to a platform that pays them to interact.

Wait, but what if facebook pays you to interact? It doesn't matter, if facebook makes a system that pays you to interact it will lose grandma, and when it loses grandma, you'll be free to pick the best platform for your paid social interaction, and I promise you, that's not going to be facebook. Why? Because facebook doesn't have their userbase locked in an ecosystem like apple, or to a lesser extent, google does. They want to, oh they really really want to, but I reckon they're too late.