The author has explained the problem with eventual consistency and the CAP theorem, but he is trying to blame the problem at least partly on CQRS/ES - the probl

The author has explained the problem with eventual consistency and the CAP theorem, but he is trying to blame the problem at least partly on CQRS/ES - the problem will exist independently of what pattern you use if your system is distributed. CQRS/ES is a pattern and doesn't need to be shoe-horned into every solution. I work at Transport for London and we have a CQRS/ES system for managing the data driven design data. It is synchronous and is incredibly useful for ensuring it has both strong business logic and a fast readable side, while providing auditing for free. We still have problems with EC and CAP, and they are not due to CQRS/ES. Make the system distributed and you will have to handle all the new scenarios. Those are the trade-offs.