Jon Crooks responded on Forum Oxford with some good insights (I only quote a small bit below). I tend to forget sometimes the fundamental differences between GPRS, UTMS, Edge, HSDPA and that's where an experts view is really what it needs. I'd like to see more people like Jon having open blogs, so that a good conversation in this space can take place.

There are some fundamental differences between how GPRS and UMTS data services are delivered over that most scarce of resources, the radio (and I include the cost of the relevant infrastructure here as well).

In short GPRS access effectively competes for voice access in the 2G network - so any attempt to offer a flat fee model has to consider the potential lost revenues from those voice calls that cannot now be made due to lack of bandwidth.

For UMTS - this is largely unused spectrum at this time and there is plenty spare for devoting to data services - such as the 3G data card package. 3G is not a service but a network capability and at the moment the voice services on offer over 3G are not very compelling - thus there is very little take up in the consumer market. However data services (mobile web browing from a PC, corporate VPN etc) is quite compelling at up to 384KBps and this is a differentiated service - hence the offer of flat rate packages. Granted sometimes there is no 3G coverage and they use GPRS (thus getting back into that lost voice revenue issue)- this is just something VF has to live with in order to promote 3G services.