Re: VM Tosh....
"If I sell you 4 apples for £1, take your payment and then tell you "Actually I don’t have 4 apples as I have to save some for my other customers, you'll just have to make do with 2 apples" I'm guessing your response will be "OK, then I'll have half of my cash back" (if I'm lucky) or "shove it I'm never buying apples from you again. A crude analogy I know, but I feel it accurately makes my point."
I think your analogy is excellent, but for me it neatly highlights the issue at hand. When you buy Broadband you are effectively paying a price based on two main variables ; how fast, and how much. How fast used to heavily dictate the price, but now BT have changed their wholesale pricing model where the provider pays the same amount whatever the line speed, what is now more important is how much. The problem is most providers sell based on how fast, and so the main variable of cost at the back of the business case isn't cleanly linked to the price variable at the front. It's no surprise customers get confused.
Using your analogy, the fruit seller is buying their apples by weight, but selling them by unit. It is in the fruit sellers interest to by lots of small apples to have the best chance of making a profits, but this upsets some customers who are used to grabbing the biggest apples first..
..OK now I've killed that analogy dead lets move on ;)
 Time is also a variable, but not one many providers have picked up on so far, so it's assumed Broadband is still 'always on'