But in this case, it is like saying "You don't need a fuel truck. You can transport 9,000 gallons of gasoline between cities by gathering 9,000 1-gallon milk jugs and filling each, then getting 4,500 volunteers to each carry 2 gallons and walk the entire distance on foot."

In this case, you do just need a single fuel truck. That's what it was built for. Avoiding using a design-for-purpose tool to achieve the same result actually is wasteful. You don't need 288 cores to achieve 243,000 messages/second. You can do that kind of throughput with a Kafka-compatible service on a laptop.

[Disclosure: I work for Redpanda]