The binary approach is that it either isn't considered or people opt in for all of it without consideration for what is actually needed. The Google SRE book goes into this at length. For each service, they define SLOs and make a considered decision about how to meet them.
Oh, so what you're saying is that they're no considering the notion that there may be a medium-availability (for lack of a better term) solution, which could be perfectly adequate/appropriate?
I assume I'm missing some meaning here, particularly since the premise of much of the discussion in the thread is that there can be high availability at one layer, but it can rendered irrelevant by a SPoF at another (especially when the "layer" is the provider of all of ones infrastructure).
Do you consider that a version of "none"? Or are you pointing out that, despite the middle ground under discussion, the "binary" approach is more common, if not more sensible?