I think the key irony underlying Bob's description of the accounting app is that he has, in fact, chosen an architecture. And he has done so quite early. The choice to structure the application in terms of controllers and entities is precisely an architectural choice.
I agree, and the choice to defer decisions (e.g. through the use of layers, adapters, etc) is also a significant decision. People often tell me that they use an ORM (e.g. Hibernate) in order to defer the database decision. Of course there's still a significant decision here ... but it's the ORM rather than the database. Significant decisions don't necessarily disappear, they just move elsewhere.
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