[bombcar]

It depends on what the purpose of the firearm is for.

Play-guns for the shooting range? Sure, add fifty safeties if you want.

But guns are used for other purposes, and there is a failure mode where the person holding the weapon intended to fire and end someone's life and the gun fails to do so because the safety was still engaged.

Many things are purposely designed "fail-safe" but some things are designed to "fail deadly" for very good reasons.

And I wouldn't be surprised if the negligent discharges that can be categorized as "I thought the safety was on and was pulling the trigger like a moron" is much higher than "I knew the gun only had a grip/trigger safety and was pulling the trigger like a moron".