You mention in one of your responses 'publishing people value manners,' and you often urge politeness, but surely it cuts both ways. I submitted a query to an agent a couple of months ago but, receiving no reply after six weeks, I queried another agent and am still waiting for a response. Yes, their websites said they were open for submissions and, yes, I did follow the submission guidelines conscientiously.
If they are not interested it surely takes only a couple of minutes to hit the 'reply' button, type 'no thanks' and hit the send button. Getting no answer at all is worse than getting a knock-back. Incidentally, I have also queried agents in the USA and UK and usually get an answer within a day or two, albeit sometimes automated. Should I contact agents who fail to respond and ask (politely) whether their email or mine has gone astray?
Yes, it cuts both ways. I've never said that it hasn't. But if you have read other entries on this website you will also have read about the restrictions on time and resources for agents, particularly in Australia. Most of us don't have assistants. Most of us are trying to fit in the submission-reading and submission-replying in our private time. The agents in the US and the UK usually have administrative help, so they can turn around submissions faster.
You'd also have read that a couple of months is really not a long time in publishing. We do the best we can - honestly, we do. But you probably would not believe how many submissions we receive if I told you. If I spent my time only reading submissions, I still wouldn't get through them at a pace that would satisfy the authors who sent them. Because the other side of this is that many authors take ten years to write a novel and then want a response to a submission within ten days. Our reading takes time, just as your writing did.
Is this slow-response situation ideal? No. I would love to be able to get back to submissions faster than I do - I would love to spend a lot of my time reading submissions. But my clients come first. And I also have to be mindful of my relationships with publishers. They take time too. I do always have it in the back of my mind, though, that the people who sent in submissions need an answer. So if you send an email after a few weeks reminding me about your submission, that is completely understandable. Check the submission guidelines first, though. Some agents say how long they're likely to take to respond. If they don't, then eight weeks is a reasonable amount of time after which you can remind an Australian agent that you exist. If they do, then wait however much time they've said and then another week or so, and then make contact. Just don't call unless they specifically say you can. Just as you wouldn't believe how many submissions I get, you wouldn't believe how many people call, and it all takes time away from getting our work done - and getting to your submission faster.