Indeed, I've seen this happen first hand where there was really only one guy who really "knew" Kafka, and it was too big of a job for just him. In that case it was fine until he left the company, and then it became a massive albatross and a major pain point. In another case, the eng team didn't really have anyone who really "knew" Kafka but used a managed service thinking it would be fine. It was until it wasn't, and switching away is not a light lift, nor is mass educating the dev team.
Kafka et al definitely have their place, but I think most people would be much better off reaching for a simpler queue system (or for some things, just using Postgres) unless you really need the advanced features.
I'm wondering why there wasn't any push for the Kafka guy to share his knowledge within his team, or to other teams?
Multiple factors (neither a good excuse, just reality):
* Lack of interest for other team members, which translated to doing what they thought was a sufficiently minimal amount of knowledge transfer
* An (unwise) attitude that "it's already set up and configured, and terraformed, so we can just acquire that knowledge if and when it's needed"
* Kafka guy left a lot faster than anybody really expected, not leaving much time and practically no documentation
* The rest of the team was already overwhelmed with other responsiblities and didn't have much bandwidth available
* Nobody wanted to be the person/people that ended up "owning" it, so there was a reverse incentive
Interesting, thanks!