The Basic Idea: Bran influences the events of the past as he witnesses, thereby causing some of the present-day occurences on the show. Namely, Bran drives King Aerys mad and convinces his father to foster Jon Snow as one of his own.
The Problem: The only evidence we have that Bran can influence the past is that young Ned Stark seems to hear him during a particularly crucial flashback. It's all assumption though. Maybe Ned's looking to see if anyone was around. Maybe he just hears a whisper on the wind. And even if Bran could be heard, how much can he actually change? We're leaning way too far into these visions. The Three-Eyed Raven has already told Bran plain and simple: the past is already written. Furthermore, these visions seem an awful lot like dreams. Bran goes to sleep to project his consciousness. Even if he's interacting with these individuals in his visions, there's a big chance his dreams are not the same thing as the actual event in reality. Plus, how could Bran cause so much damage under the Three-Eyed-Raven's watchful gaze?