While not wrong, everything breaks at scale. Everything. Anyone that says otherwise is just not interested in talking about where what they built will break.
And note that this is more than just scale of use. It is also scale of development. Keep adding changes to something, and it will break. Stability of application requiring stability of development is just not something we care to admit, that often.
That is, don't hide when/why something will break. But also don't get blinded looking for how to avoid all breakage. If you can, find ways to isolate failures and block off entire sections.
This is good advice. You should be aware of who you are building for. Designing your system to run on 100 containers orchestrated by Kubernetes is overkill for your average SaaS MVP, while counting on shell scripts is a recipe for disaster at FAANG scale. Scale matters.
Don't just look at the execution you are building for, but also the team that will be maintaining it. That is, there are several values for "who" that you are building for. Each will have cause for you to reach to more complicated seeming solutions, as you go.
And note that this is more than just scale of use. It is also scale of development. Keep adding changes to something, and it will break. Stability of application requiring stability of development is just not something we care to admit, that often.
That is, don't hide when/why something will break. But also don't get blinded looking for how to avoid all breakage. If you can, find ways to isolate failures and block off entire sections.