The reason why the persistent reply to example at the nabble discussion, is because Camel will have to use a Dummy value for JMSMessageSelector when there is no expected replies to receive. And it thus takes 1 sec. for it to timeout, before it can update the JMSMessageSelector with the CorrelationsIDs to receive.
We may try to suspend/resume the message listener container, but we could potential end up with some synchronized issue where we would suspend the listener, where as in the mean time on another thread a new message is being send. And thus we may miss resume the listener. Therefore we end up not pulling the message from the AMQ broker.
We should add some documentation / FAQ as the drawbacks of using persistent queues.