It’s a good theory, and definitely something you should be aware of but... in my experience if the producer fails, you get nothing (of course), and if the consumer fails, the messages just back up until the queue overflows and of course if the queue itself fails - which can happen due to hardware or network as well as software issues - you have a new point of failure that’s unrelated to the producers or consumers. So the whole thing is only as good as the responsiveness of your monitoring team... which is effectively the case with synchronous message delivery, only with the added complexity of troubleshooting the queue in the middle.