A word of explanation is due with regard to Weems v. United States. In 1910, the Phillipines was a territory of the United States, having been acquired in the Spanish American War. The case was appealed to the US Supreme Court from a Phillipine Court. Hence the disparity in sentencing norms.
That leaves us with Rummel v. Estelle, and Solem v. Helm, and all we can say from that is that the Supreme Court has not figured out how to get comfortable with something for which there is no quantitative rule book. I believe that cruel and unusual is a possible ground for future litigation. There is one judge who believes that societal norms might be a good place to start. I am particularly interested in cruel and unusual with respect to the Venezuelan migrants. I have a hard time categorizing prison for life in a prison with the reputation for having no one ever come back out, in a country having no relationship to the deportee, as other than cruel and unusual.