[doseofreality]

In Agile, as implemented at most non-consulting shop places, the Product Owner really doesn't have the authority to block things coming into the sprint being pushed from executive staff, important customers, or sales. The PO just acts as a point of contact/funnel to push the stuff coming in from these places into the sprint.

[TheCoelacanth]

You can't really blame the process if you aren't following it.

If your assertion is just that most companies suck at developing software, then I agree with that. However, it isn't because they are following Agile. In most cases, things would be somewhat improved if they followed Agile more closely.