> We don't say "Everyone needs to care about software architecture, even Product"

We absolutely should say that. I was an engineer for 13 years and have now been in Product for 8 years. I work on a highly technical Product team, and it is absolutely an expectation for myself, my peers, and my reports that we should ensure we fully understand our Product, including its software architecture, and have an opinion about it. Engineering ultimately decides the "How", but they cannot do that effectively if Product cannot articulate an opinion about the architecture guided by an understanding of things like expected scale, potential future integration decisions, and other cross-organizational expectations that may not yet be codified. In general, Product should have an educated opinion on anything that is a one-way door, and so should Engineering. It should not be a unilateral decision, and if either party is unable to form an informed opinion, that's an organizational miss.