People don’t care about the real MLK or are afraid to tell the truth. If he hadn’t been murdered, he would have faded into obscurity. As it happened, though, the left decided he made a convenient a hero once he was dead.
In reality, Ralph Abernathy and others probably did more for getting rid of segregation, and Abernathy wasn’t the sleaze that MLK was.
Having lived through those times, I think that even if he hadn’t been murdered, his name would be alive...however, he was heavily influenced by leftists, was not a leader but had good stage presence, and would probably have been only one of the several people credited with leading the civil rights movement.
The problem with MLK is that because he himself was not an original thinker or leader, it was very easy for the left to coopt him and make him their symbol. One of the reasons many people in the South at that time, including the Archbishop of St Augustine (Florida), didn’t like him was not because of his civil rights activity or his color, but that because they thought he was a Communist. The poor guy probably didn’t even realize this.