I don't think the effects are as drastic as you'd think since all of the crimes listed by the OP carried the death sentence in many places throughout history yet you still had plenty of crooks who did not resort to murder to kill witnesses/their victims "just because they could".
Did abolishing the death penalty for rapists and child molesters decrease the number of rapists and child molesters who were also murderers? I'd like to see some research on this.
Your right, whatever the penalty is crime, and degenerate, sick behavior continue. Nothing is new under the sun. Fear of punishment has only a limited effect on human behavior. There are lots of factors in the rise, and fall of crime rates. The death penalty is a measure of our outrage, and judgement that an individual is irredeemable. Hope of redemption, and the value we place on life further mitigate against capital punishment. It's my understanding that the United States has never executed more then about 30 people a year, and that was in the crime ridden 1930s. This OP would bring that number up to hundreds of thousands a year, which is unthinkable, in any America I could imagine.
Interestingly with all the recent talk about America's ugly history of Lynching, the Lynchers would have to be executed. Since so many of those killers were shielded, in many cases by local law enforcement, those lawmen would be executed, and all who abetted them to. In the age of ME TOO the list of rapists, and sexual assaulters in high places, (Going all the way to the very, very top.) seems longer then we ever thought. Every 18 year old, who had sex with a 15 year old goes to the gallows, with the rest. It just goes on, and on. So the World is left Blind & Toothless.
One last thought. Knowing that these crimes would be punished with death juries would be loath to convict, in all but the worst cases. Prosecutors have many times seen defendants walk because they overcharged them, and the jury wouldn't go for it. The state wins over 90% of the time, want to see that ratio reversed? Oh and by the way, why not include indirect murderers, like drug dealers, or the heads of Pharma who knew how dangerous the opioids they were selling like M&Ms were, then lied about it? I personally don't see much redemption in that cast of characters.