I have an entire database that tracks how long mainstream media covers mass shootings. It's insane how quickly the news cycle moves away from coverage.
The Las Vegas Massacre was covered a mere 9 days before MGM got involved, threatened to pull all advertising from mainstream media that continued coverage, and that was that. Once it was determined that there was NO clear motive, radio silence. (A sporadic blip about funerals, a 20/20 piece on citizen heros, and it was a wrap.)
Here is how insignificant El Paso and Dayton were:
31 people died in El Paso, Dayton mass shootings. Twitter data shows talk faded in just 10 days.