Is automation bigger than DevOps?
We think that the canonical answer is yes, automation subsumes DevOps. Some professionals think in terms of automation, and automation existed before DevOps was a word. It is well known that the Toyota Production System has influenced DevOps. Automation played a big role in the success of Sakichi Toyoda.
His "most famous invention was the automatic power loom ["a hand-operated or power-driven apparatus for weaving fabrics", taken from Dictionary.com] in which he implemented the principle of Jidoka (autonomous automation). The principle of Jidoka, which means that the machine stops itself when a problem occurs, became later a part of the Toyota Production System." Taken from Wikipedia.
Automation may seem commonplace. But it is quite complex. Sophisticated automation in I.T. uses DevOps. To be fair, some people would consider DevOps to be a field that leverages automation; this characterization would render automation "smaller" than DevOps. Page 360 of The Phoenix Project (5 year anniversary edition) says 'As Christopher Little, a technology executive and one of the earliest chroniclers of DevOps, wrote, "DevOps isn't about automation, just as astronomy isn't about telescopes."'
In some ways automation and DevOps are different subjects like the same way biology and chemistry are different from each other. To the extent that they are related, automation predates DevOps. Automation is central to I.T.