For what it's worth, I've never been on an agile team that did not have some waterfall decision making that was not open to correction, or a waterfall-based process that was totally closed off to testing and making changing along the way. I think we argue about platonic archetypes that don't exist in reality. Most processes and teams I've worked with have resembled each other more than not, if you ignore the terminology they use. I think success or failure of a project comes down to a lot of factors that are hard to quantify, so in some sense our focus on process methodology is a bit ritualistic and cargo culty.