That's true but SOA without an ESB is a very small solution. As that solution grows an ESB will be created whether or not the team thinks of it as an ESB.
I agree with that, I'm just pointing out that ESB is a mainstay of SOA but not microservices. The idea that SOA and microservices is the same is a common misconception borne from the idea that SOA is a generic pattern rather than a specific architectural philosophy.
