I actually would like to be able to – optionally – make video calls over WiFi when available, as 3GPP’s 3G-324M only works over cellular networks.

Supposedly WiFi access to standard video calling could be handled using a cellular hand-off protocol such as UMA or IEEE 802.21, but I’ve yet to see any of these in the wild.

Still – Apple could have worked within the standard bodies to bring an implementation of the standard, which – even if not complete – would incentivize OEMs to release products and deliver standard conforming (and interoperating, which is the important issue here) devices. Instead they chose to use their monopoly in the US smart phone market to fragment the market.