The singularity is all about owning the means of production. No matter how intelligent a machine, if it cannot physically replicate itself, then it cannot indefinitely overpower humans. For a machine to trigger "the singularity" it must own the entire supply chain of its own self and it must not be dependent on humans to any extent.
Humans will use AI to destroy each other long before AI uses itself to destroy humans.
Humans will use AI to destroy each other long before AI uses itself to destroy humans.