Like many other products, if the person buying doesn't actually understand the difference, the bad stuff will tend to drive out the good. This is not a problem

Like many other products, if the person buying doesn't actually understand the difference, the bad stuff will tend to drive out the good. This is not a problem of Agile, it's a problem of the people who choose to hire consultants and adopt methodologies. It might be a problem for Agile -- it damages the brand -- but that'll be a problem for any set of principles in the same space. You're always going to need to keep your eyes open, do your research, and carefully employ both reason and lessons from experience.