He may have had the firepower of Tess and Clem's loyalties, as well as their formidable regimes but I reckon probably not the stomach, weakened by the shooting and devastated by the loss of two sons

However if Barz and Tatt are taken out, I reckon they could win because what can small potatoes Cuneo and Stracci do?

Tess and Clem hate that goddamn Barzini! can't see them operating under Barzini's thumb
He also would have been suspicious it was a plot by Vito (a la Luca/Tattaglia) to suss out Barz's intentions

Again as we debated, in Vito's vs Michael's caporegime thread, They were already separate and independent of each other with their own separate territories and now become Don Clemenza and Don Tessio with their own separate Family

And the Corleone name lives on