The Mafia had motive but could not do the coverup. That was government.
A lot of mobsters bought Mark Lane’s book because they didn’t know and wanted to know whodunit. I don’t know all the capable hitmen, but the Families knew. Not the Mafia.
Magic bullet didn’t do it, which means Oswald didn’t do it. Available evidence doesn’t even conclusively determine where the shooter was, or whether there were one or more shooters.
LBJ knew ahead of time. The Texas governor, John Connally, didn’t know and he was so pissed he eventually switched parties to Republican. The 73 eyewitnesses who died before testifying would have provided a different picture than the official story. Dan Rather saw some details but was told to keep quiet, which he did.
Motive: LBJ had motive. Nixon had motive. Jackie had motive. The CIA had motive, plus means and opportunity. As the first Catholic President, JFK was hated by millions in the South, so hiring one or more shooters could be done.