I don't really get why LW's content isn't in mainstream academia to be honest.
This is a very good question to think about :).
It probably says some mixture of bad things about academia (e.g. fear of looking silly) and bad things about LW (e.g. insufficient money to run randomized controlled trials, insufficient dedication to cite lots of related literature for every post the way lukeprog does).
Academia has flaws, like publication bias, closed access journals, expensive textbooks that don't allow comments, slower conversations, credentialism, lousy writing and maybe tenure. Less Wrong has flaws, like the fact that all its contributors are part-time, people think we're weird, it's...
I feel that a lot of what's in LW (written by Eliezer or others) should be in mainstream academia. Not necessarily the most controversial views (the insistence on the MW hypothesis, cryonics, the FAI ...), but a lot of the work on overcoming biases should be there, be criticized there and be improved there.
For example, a few debiasing methods and a more formal explanation of LW's peculiar solution to free will (and more, these are only examples).
I don't really get why LW's content isn't in mainstream academia to be honest.
I get that peer review is not the best (far from it, although it's still the best we have, and post-publication peer-review is also improving, see PubPeer), that some would too readily dismiss LW's content, but not all. Lots would play by the rules and provide genuine criticisms during peer-review (which will lead to the alteration of the content of course), along with criticisms post publication. This is in my opinion something that has to happen.
LW, Eliezer, etc, can't stay on the "crank" level, not playing by the rules, publishing books and no papers. Blogs are indeed faster and reach a bigger amount of people, but I'm not arguing for only publishing in academia. Blogs can (and should) continue.
Tell me what you think, as I seem to have missed something with this topic.