The 3G connection does not aim to provide completely reliable "connections" -- it aims to provide an as-reliable-as-it-can data link, given channel conditions and configured transmission parameters (which are to some extent controlled by the RAN). If the error rate seen by the channel decoder is too high, it will drop a frame. There is an ARQ mechanism in the MAC layer to try to compensate so that the higher layers don't see the loss, but it implies some delay and also has limits -- i.e. at some point losses due to bit errors injected by the channel may manifest in lost frames and IP packets.

The L1 and MAC of 3GPP are generally implemented in an ASIC and not necessarily visible to the OS. Many of the parameters are dictated and controlled by the RAN (operators are picky and try to control things so that handsets can't misbehave and crap all over the other users in a cell), so the OS doesn't get a look in -- i.e. I don't think it's possible to turn off the 3G error recovery mechanisms.

Disclaimer: I used to work at L1 so someone with more detailed knowledge the MAC and higher layers of the 3GPP stack could give a better idea of what happens when the MAC ARQ limits are hit.

Summary: 3G was designed more than 10 years ago and is showing its age. User requirements have shifted, but standards can't evolve that quickly. Maybe LTE will help provide the user experience for today's apps... question is whether it will be widely deployed in time to matter.

EDIT: updated for clarity and spelling.