It is true that people in academia, as everywhere else, have a combination of low and high motives for what they do. The question is, on what grounds should one assume an average less-wronger is better in this respect than an average academic?

In my experience the biggest barrier in "mathy" areas is getting up to speed. Getting ideas accepted is a significantly bigger hurdle than getting ideas published. Most stuff that gets published is either not great or not useful (obscure) and often both.

edit: to clarify: I don't see that the way one thinks about spreading lesswrong memes is different from the way one thinks about spreading "what I have published" memes. Both high and low motives are involved in both cases, and suboptimal equilibria are involved in both cases in the sense that one must think of ways of competing with other people's memes.