Same circumstance as socialism.
This time, this time, pass just one more restrictive law, and it will work (this time, this time, just need a little more OP's money, and it will work)
IMO the agenda is otherwise. When gun control law after gun control law fails, the left sees that as incrementalism towards confiscation. They mostly loathe the concepts of personal self-defense and self-reliance, so they see no need for the peasants to be armed.