> If your queue is the bottle neck (yes it happens) how do you know there are more nodes getting added to it? How do you rebalance the topic over multiple new nodes in the queue?

In a message queuing system, there is no rebalancing - you just add nodes, which then also get messages, typically in a round-robin fashion. This is not Kafka.

But of course, you can max out your message broker. As you can with a network switch for that matter.

> oh look i got an error and retried a few seconds later

So now you need a retrying mechanism. Which is provided as a basic feature of a messaging system. And with the transactionality, you do not get the problem of wondering whether the first attempt went halfway through, or not.