Well, the advice is rarely taken in practice. It is (in my experience, and it seems common from others based on what I've heard) very very common to jump to the complicated solution at the first hint of capacity issues "because we'll need to do it eventually anyway."
The advice is obvious when you're thinking at that level of abstraction. Which suggests that, in practice, people who are architecting such systems rarely think at that level of abstraction. Which is why it is nice to have posts like this, that periodically remind us to get our heads out of the daily minutiae and consider the bigger picture (of complexity tradeoffs, realistic projections, staffing and availability, etc.)
The advice is obvious when you're thinking at that level of abstraction. Which suggests that, in practice, people who are architecting such systems rarely think at that level of abstraction. Which is why it is nice to have posts like this, that periodically remind us to get our heads out of the daily minutiae and consider the bigger picture (of complexity tradeoffs, realistic projections, staffing and availability, etc.)