Cellular Architecture was largely a reaction to the S3 outage [0]. I agree that one is still bound to fail due to unknown unknowns or unpatchable known unknowns, but reducing the blast radius [1] to not be globally unavailable [2] is a step in the right direction.
[0] https://www.youtube-nocookie.com/embed/swQbA4zub20
[1] https://blog.acolyer.org/2016/09/12/on-designing-and-deployi...
[2] https://blog.acolyer.org/2015/05/07/large-scale-cluster-mana...
