Because Seinfeld and Friends became bigger than most any sitcom before them, and now everything is trying to be the next version of that. Add in Big Bang Theory a decade later to add in the "living in LA with a theme" to the possibilities.
I'm sure there are a lot more woke type factors at play, but the foundational level is almost certainly just based on the absurd success of those urban sitcoms.
Because Seinfeld and Friends became bigger than most any sitcom before them, and now everything is trying to be the next version of that. Add in Big Bang Theory a decade later to add in the "living in LA with a theme" to the possibilities.
I'm sure there are a lot more woke type factors at play, but the foundational level is almost certainly just based on the absurd success of those urban sitcoms.