Comment by nicksnyder

The other clouds have fees like this too.

Even if this were to change, using object storage results in a lot of operational simplicity as well compared to managing a bunch of disks. You can easily and quickly scale to zero or scale up to handle bursts in traffic.

An architecture like this also makes it possible to achieve a truly active-active multi-region Kafka cluster that has real SLAs.

See: https://buf.build/blog/bufstream-multi-region

(disclosure: I work at Buf)