I think the engineer mindset is more strongly represented here than you think, but that the nature of nonspecialist online discussion warps things away from the engineer mindset and towards the scientist mindset. Both types of people are present, but the engineer-mindset people tend not to put that part of themselves forward here.
The problem with getting down into the details is that there are many areas with messy details to get into, and it's hard to appreciate the messy details of an area you haven't spent enough time in. So deep dives in narrow topics wind up looking more like engineer-mindset, while shallow passes over wide areas wind up looking more like scientist-mindset. LessWrong posts can't assume much background, which limits their depth.
I would be happy to see more deep-dives; a lightly edited transcript of John Carmack wouldn't be a prototypical LessWrong post, but it would be a good one. But such posts are necessarily going to exclude a lot of readers, and LessWrong isn't necessarily going to be competitive with posting in more topic-specialized places.
In light of reading Hazard's Shortform Feed -- which I really enjoy -- based on Raemon's Shortform feed, I'm making my own. There be thoughts here. Hopefully, this will also get me posting more.