Having worked for Royal Mail in the past i was involved in the barcoded mail and been inside many a mail centre, local sorting office and even some of the big air mail units including Heathrow....the amount of mail flying around at any one time is huge so as you say its unlikely that the odd blip isnt going to happen. Costs are going up and whilst Royal Mail have to serve the whole country the others can pick and choose where they deliver to. Was once told that some of the competitors will actually use Royal Mails service to reach some outer areas like the top of Scotland etc.