I completely agree and love the sentiment here, but I'd modify it slightly. What the author is saying is that you can't get a person to go from 0% to 100% understanding just by telling someone. The avatar example is great - you're not going to convince people 100% that avatars are game-changing by telling them once.
On the other hand, incremental nudges are possible. e.g. when you tell someone "hey, we're going to have avatars," you might nudge from from 0% to 1% conviction that avatars will be interesting. Maybe that seems pretty useless...
But there's a way to harness it! One way to tell someone something and have them actually understand it is to have them engage in long-form content. Have you ever wondered why books need to be so long to explain topics which you could summarize in a sentence? It always perplexed me why authors like Malcolm Gladwell could write for 50k words what could be distilled into a couple of sentences, or why talks spend 60 minutes going over a couple of points that someone would summarize in a few bullet points on a YouTube comment. But eventually I realized that the extreme verbosity is crucial. You can't bring anyone from 0 to 100% understanding in a single sentence, but if you string enough sentences together, and attack your point from enough unique directions, then you really can start to move the dial.
The problem is that when you talk to someone and you say "avatars are coming!", you've got this big picture in your head of what that could possibly mean, you've thought deeply about all the possible ramifications and associations that avatars bring, and your sentence has so much implicit meaning to you. But since no one else you're telling has that knowledge, that sentence only carries a small sliver of the full context and meaning that you understand. To really get it across, you need to convey your entire context. Which takes a really long time.
And that's why you can't tell anyone. Well, not easily.
P.S. This comment got so long that it came dangerously close to wading into meta territory, but I managed to successfully avoid it. Oh wait.