I swear to god, when I bought my Droid 1 no one at the VZW corporate store said "this is a computer" nor did they say "you've got unlimited data go nuts".
The simple fact is a cell tower can only carry so much traffic. Period. It's also quite expensive to put up cell towers, and in many communities where towers can go is very limited. My town does not allow towers within its borders, except in two very specific locations. That's it, VZW, Sprint, AT&T, T-Mo can't put up any more. Many communities consider them eyesores and cannot be put up in residential neighborhoods. I doubt you want a tower in your backyard.
With that in mind, there is only so much a provider can do. One thing they can do is put some sort of limit on how much data can be used.
Firstly, no one here has a clue what this magic 5% number actually relates to. Everything mentioned is speculation. Someone back a few pages stated that while he would agree that phone calls and emergency calls trump his "need" to download movies on his phone 24 hours a day, he doesn't think someone using opentable once a week should get any preferential treatment over his 24 hours a day of usage. That's insane, and that behaviour is the reason ALL wireless carriers are trying to figure out what to do. Even the CEO of Sprint has stated that "unlimited" plans will stay around until they get abused. One of the reasons Sprint doesn't have this issue is that they have far fewer users than ATT or VZW. If Sprint had twice the customers they have now, I betcha they would have to impose some sort of reasonable limits too.
There are plenty of people on this board who abuse the ToS they have with VZW (rooted so they can wirelessly tether w/o paying any fees, using PDAnet etc to tether via USB w/o restriction). Wireless data on your smartphone doesn't mean "oooo let me hook up my home computer to this phone so I can dump Comcast".
If they start cutting back service at 2GB, that is something to ***** and moan about, but if they start cutting back at 10GB, I say good for them as it gives me faster access.