Yesterday, I tried to create the "Laravel" site and it got flagged as a duplicate. But yet there are other frameworks such as "Wordpress" & "Drupal" who got their own SE site. So what is the guideline that determines what can become a site vs what can not?
The first criteria we look at when considering a proposal is whether the questions could already be answered on one or more of our Stack Exchange sites.
We don't generally split off a community from a site simply to give a topic its own space. Wordpress and Drupal are end-user products with considerable ecosystem of questions beyond programming, and the content management systems in particular host a lot of end-user questions which don't fit on Stack Overflow at all.