Calling MSK expensive is maybe not being clear enough. It's more than 2x the cost of the raw EC2 instances. Then on top of that, to get metrics at the per broker level there's an upcharge, and a further one for per topic metrics. These are things that are actually extremely important at scale, and it's absurd how expensive it gets.

Then you combine that with how immature the UX is, and it really just doesn't feel good to deal with. It's not that much work to run a Kafka cluster with the sort of design that MSK provides, and it can be done better than that without much cost.