This community is user driven, and our most popular questions are asked by users of all experience levels and applied areas. Meta-questions like yours have been asked: "Why don't we have more questions on X?" And the answer is very obvious: Users of this site aren't coming here with curiosity/knowledge about X. The SE platform synergizes topics: questions that get frequent answers, upvotes, edits, and comments are exponentially more "bumped" than they would be in say forums (perhaps less so than in Reddit).
That doesn't mean the community is unable to support questions tagged sem or related. SEM is conceptually easy to do, but challenging to implement. The open-source alternatives are shoddy and can be tough to use, lavaan
is perhaps one exception; OpenMX
is almost impossible. M-plus is non-free software with a vibrant support community. The Muthens have provided detailed examples and discussions, and they frequent their own board answering forum questions fairly politely. Paid software users like to utilize the support services they have exclusive privilege to. On those boards, syntax and conceptual questions are on-topic.
In contrast, a large proportion of CV users are R users. While we now close strict R questions, a majority of questioners use R code or data to illustrate a problem and are looking for R code in an acceptable answer. Most of the time, answerers can fire up an R session and load that code, example data, and provide new syntax or plots to illustrate problems. R simulations to theory questions are frequently accepted answers here. To a lesser extent this is also true of Python. Contrast this with questions that use/illustrate a problem with Stata or SAS code: they go virtually unanswered.
I suspect the community will be challenged by lack of access to M-plus, even in questions not directly about M Plus, and the popularity/accessibility of these questions will be somewhat low.