I am going to make some very clear predictions right here so that I can refer back to them later.
Effective altruism will never succeed as a social movement. By "social movement," I mean as something that applies to all or many aspects of life and not just charity. I think GiveWell and other charity evaluators have found the area with the most potential and they will succeed in this area.
Those trying to apply EA to other areas will struggle to convince others to follow suit. Only a few more people will completely change careers based on EA considerations. Very few will ever optimize their free time so as to maximize their positive impact on the world. Very few artists, for instance, will ever compromise their artistic vision for the greater good. Pushing in this direction is more or less hopeless.
Moreover, I think applying EA to complicated issues can easily do more harm than good. As a general rule of thumb, the more simple something is, the better we should be at optimizing in that area. Donating to charity is one such area: saving more lives is better than saving less lives, preventing more suffering is better than preventing less suffering, and more money can go further than less money can. Attempts to optimize highly complicated areas like life trajectory, culture, and art have to be very cautious.
Obviously, if we could actually optimize those areas, that would be great. But most likely, there are only little pieces or broad trends in these areas that we understand well enough to mess with. My impression is that most people in the "EA community" are trying to optimize things that are too complicated to optimize.
I'd like to point out that I distinguish between "EA: The Community, Culture, and Movement" and specific beliefs that EAs believe and promote. I think the former is somewhat limited in its potential growth, while some specific EA beliefs may spread far and wide. I also think the existence of a social movement surrounding EA can actually limit the persuasiveness of specific EA beliefs because people don't want to feel like they're joining a club or changing ideologies by accepting 1 or 2 EA beliefs.
I predict that in a few years the term "effective altruist" will be publicly damaged by attempts to apply it to areas where it just isn't useful. At that point, people will have to toss the word out and find a new label because the current one will be considered a pejorative.