I expect Argentina to be physical and even a little dirty, but what they lacked was control - not just defending, though I agree with you, but the ability to manage the tempo of the game. They knew how to attack, but behind that attack was a lot of confusion and fear.
Sampaoli seemed to favor an aggressive approach, pressing the opponent. This is a tactic that works well but only when employed by a well-drilled unit, and international squads have less time to train together than club sides. It seems Argentina simply weren't able to adapt to his preferred approach in time. His flip-flopping between a back 3 and back 4 seemed desperate flailing rather than clever tactical shifts.
The necessary pieces are there, but as a unit Argentina either didn't have enough of a plan, or weren't ready to execute it properly, or both.
Contrast that to Iceland, who are very light on talent but a wonderfuly cohesive team who knew exactly what they were supposed to be doing. They punched WAY above their weight. Imagine how dominant an Argentina squad with the same level of preparation and confidence could be.