is that the community is in need of growth. My interpretation of this is as follows: the Sequences are not updated, and yet they are still referenced as source material.

I don't see any connection between growth and updating unless significant cognitive science breakthroughs were made since. But I think growth would depend on presenting it in a popular, digestible format. Not HPMOR, not one book and not a book for SF/F nerds anyway... but more going to say changemyview.reddit.com and engaging in debates and when people make cognitive mistakes linking to the article here. For example. Or people who have commit privileges to popular newspapers could write articles like "10 things LW taught me".