Would there be less homicides if all the guns disappeared magically? Almost certainly.
Your conclusion is presumptuous. Humans did a damn good job of killing one another before firearms were invented, and they continue to do so today at a significant rate even when a firearm is not involved.
I hate to put it this way, but most people who would use a gun to commit homicide are not the types to do the job 'by hand'. Guns make it safer for the person committing homicide with the gun
The rate of homicides would certainly go down without the use of guns. It wouldn't hit zero, and would slowly increase after the initial decline, but it would never reach the same rates as when guns were available. I'm not blaming the guns, it's absolutely the people using them. I'm sure the number of accidental deaths would decline if cars were outlawed, but that doesn't mean it's the car's fault.
The vast majority of gun owners are not murderers. Venezuela's ban on guns is the government's way of disarming the citizens so they can continue to chip away at their other rights without the government having to worry about the citizens rising up to fight back.