In days gone by, the WTS actually did focus on inviting the public. My grandparents told me about handing out invitations to the public talk to people as they left church on Sunday. The talks were held Sunday afternoon or evening so that people could go to both. They also would wear placards with the public talk title, date/time, location, and sometimes speaker on it. JWs would routinely hand out handbills to everyone they contacted that week with the same information. Bible students and families were targeted.
Now most public talks are routinely scheduled during the prime church time with the assumption that few people go to church any more or that people who would go to the KH don't go to church.
Talks were more focused on subjects that would appeal to the public; now they are designed more for the rank and file. In spite of the official counsel from the WTS to leave out terms like Babylon the Great, new system, etc., most speakers use terms that only baptized JWs comprehend.
There was a time that there was neither a prayer or a song before the public talk in deference to non-JWs; this included the talk at the assemblies/conventions. I think that changed in the early 70's.
So the talk was once more focused on appealing to the public.
Now the only non-JWs are unbaptized, minor children, the occasional visit by a non-JW spouse or Bible student.
Blondie