Viewing architecture in the context of a scrum team is risky, since you need a level at which the overall system can be thought about. When a development operation has multiple scrum teams (which is more often the case than not), the tendency is for these teams to silo themselves, and to build multiple independent and often incompatible "products". What you get is a hodge-podge mix of semi-usable features. The reality is that you need Architecture in the teams, but also outside the teams. Architecture needs long lead times to fully digest the domain and its idiosyncracies. Architectural design can be done in scrum teams, but it should only ever do so in the context of the overall vision for the product. Agile works best when the context is clear, and it's the role of an Architect to provide that context.