Having been born in 1950, I was fully engaged as a news junkie during the Kennedy years. Watched TV news, read the newspapers, and read US News & World Report.
The country was shocked and in grief, but not for “months.” There was plenty else to occupy the minds of the masses. And Johnson was savvy enough to keep his face on TV enough to calm anyone who thought there was no one in charge.
Also, on Feb 7, 1964, The Beatles came to America, and that event was of sufficient impact to distract everyone.
Remember too, the civil rights struggle was ramping up at the time, and it was quite the news event.
I was reading your post, and thought f the event that got us out of the funk after the events of Nov. 1963, and thought of the Beatles, and then you said it in your post.
In 1964, The Beatles were good for America, and America was good for the Beatles.