Its because the branching story was an illusion. You think you have the choice of what to do, with all the dialogue options, but ultimately the choice is the games and the closer you get to the end of the game the more apparent it becomes as it hastily funnels you to the finale.
No… RCS is a protocol (from GSMA) anyone can implement, Google just spearheaded it and developed Jibe to make it easy for operators to implement, but by doing this it means Google gained a lot of control of it and added their own features to such as end-to-end encryption.