Agile software methods (and Scrum in particular) have been the go-to development process for most software shops, at least in silicon valley. There were almost no shops doing anything other than some form of Agile, or Scalable Agile.
But Agile and Scrum have their challenges. Perhaps the biggest challenge is that the needs of the business and the needs of the product team can get afoul of each other. This can happen in many ways, and some would say that Agile was designed to fix many of those problems. But the fact is that they persist. They are slightly different now, but the challenges remain.
One big challenge is that the business will often want to change priorities based on business needs, and this is often presented as "being agile." We hear this all the time. "We are an agile business, right?" But what happens next is where the problem starts. Quite often, the development team will have to scrap what they are working on an change gears to meet the "new priority."
But now the business wants to know what happened to the previous promises made by development. "What happened to the thing you promised last month?" This interaction can be very disruptive to the entire process and the morale of the teams. We believe that a modified "time box" approach can alleviate many of these issues.