Bandwidth
I worked at a cable co in the US for a few years. My experience has been that these (US) cable companies never have enough resources for the amount of users, in hopes that not everyone will jump on at the same time, thereby increasing the savings(profit). They even do this with DHCP leases for the devices attached to the CPEs. To save on server (and admin) costs, they don't have as many IPs as they have customers, and usually that works out OK. But then again, when everyone DOES get on at the same time, suddenly we're running out of IPs, the backbone latency starts to skyrocket (in a bad way, similar to DDOS...think 5 DS3s and a handful of DS1s connecting us to the big-boys (sprint, verizon, etc...), trying to feed ~10,000 subscribers, using 3 or 5 Mbps cable connections), and the tech support lines get so flooded they ring busy. Most customers know there is a system problem by that busy ring. What we aren't allowed to tell them is that although we accept payment for a service advertised as 3-5mbps, we don't have the capacity to allow every paying customer to get that throughput to the internet at the same time. What the customer is told when they call in is that "While we can't guarantee you will be able to obtain 3 or 5 mbps through our backbone to the big-boys and the internet, you ARE getting the 3 or 5 Mbps they pay for, and if you download a file from OUR SERVERS you will see the appropriate download rates. "
Sure you don't have to provide 3 or 5 mbps if the fine print reads 'actual rates may vary according to insert-PR-BS-here'; but that's just poor customer service, and that's why it is wrong.
Who in their right mind thinks a customer will happily (and knowingly) pay for the 'ability' to connect at those speeds, when they can't be reliably utilized?
As an analogy, some customers would call and ask if switching from 10mbs LAN to 100mbps LAN would improve their internet, and obviously, you're connection to the modem is 10xs faster, but not anywhere past that point in the route. All of them said something to the effect of 'then why bother paying to upgrade?'.
If the customer can't realize the value they are being sold on, they WILL leave, in search of something better, or at least more transparent. Also, I am highly suspicious of any company that blames their problems on their customers. It IS the companies responsibility to adapt to the customer's needs and want's, otherwise, someone else will, and you're left SOL, with no revenue.
You could say customers 'might' reach the full bandwidth potential they were sold on, causing a loss of service or high latency for other users, or you could just as easily say it is VM's fault, for not having the infrastructure that 'might' be required to keep everyones service usable. It all depends on which end of the fiber you look from, and which dotted line you signed on (or didn't). From the customer's point of veiw, 'Page cannot be displayed' means 'the service you are paying for is no longer available'. Even if it's wrong, that's what the customer expects, and if that can't be provided for, the customer will find someone who can.