> What's your response to the common theme that event sourcing systems are difficult to maintain in the face of constantly changing product requirements?

I've been on an ES team at my current job, and switched to a CRUD monolith.

And to be blunt, the CRUD guys just don't know that they're wrong - not their opinion about ES - but that the data itself is wrong. Their system has evaluated 2+2=5, and with no way to see the 2s, what conclusion can they draw other than 5 is the correct state?

I have been slipping some ES back into the codebase. It's inefficient because it's stringy data in an SQL database, but I look forward to support tickets because i don't have to "debug". I just read the events, and have the evidence to back up that the customer is wrong and the system is right.