There's been a theory floating around the internet that Thanos waited so long to make his move to assemble the Infinity Gauntlet because the most powerful beings in the universe were still alive. The characters I am talking about are Odin, Ego the Living Planet, and the Ancient One. (See, for example, this article on Inverse.com.)
I re-watched Doctor Strange recently, and in that movie, after the Ancient One's death, Baron Mordo states that news of her death would spread throughout the universe.
I personally don't subscribe to the theory that Thanos waited for these people to die (Thor: Ragnarok takes place too close to Avengers: Infinity War for news of Odin's death to spread that quickly), but have the Russo brothers or the screenwriters commented on it? Is there any truth in the internet's words?