Unfortunately I can't offer a reasonable explanation. As with most things aviation recruitment related, there is often no logic, just luck. Perhaps they're too busy to say thanks but no thanks, and they only have time to deal with successful applications. Again, I'm sorry to say, but thinking that they haven't read your application as to a reason why you haven't heard back, is most probably wishful thinking. If it happens to me, I tend to 'get the message!'
I learned yesterday that one lad that got into BA (where I didn't) is the worst, most arrogant pilot we had. Not to mention always in trouble with the law, and yet BA wanted him over me. So good at bull$hitting, even BA couldn't see through it.....way of the world!
Chin up!