Outright Incompetence
O2 seem to be quite happy hoarding iPhone users vast subscription fees without realising that they have to actually invest in their network and adapt their entire business model to cope with the sea change that Android, WebOS and iPhone OS's are able to do. These devices are by all intents and purposes extremely portable computers that only require data access to the mobile internet, with only a few concessions to existing services like GSM calls (instead of VoIP) and SMS instead of IM.
It is time that O2 and all the other mobile networks actually realise the day and age of everything-over-IP is here already.
With Sky having to ditch their satellites (that are overdue to fall out of the sky anyway) in favour of delivering content over IP (hence the real reason behind Easynet's acquisition), with BT already offering a rather feeble IPTV service in BT Vision, Virgin Media having the infrastructure but too stupid to take advantage of it, and needless to say VoIP being a mature technology already adopted by just about everyone except possibly your nan.
Mobile networks have to realise that they are effectively mobile ISPs now, and that all service plans should be based around unmetered data plans.
Point is O2 have failed to realise the sea change they need to do in regards to changing their mentality, business plan and adapting their network infrastructure to support the new age of mobile ISP. The concept of pence-per-minute call costs and the ridiculous charges for sending a few characters in SMS is over, and the networks have to realise this.
No amount of grovelling will help here, because at the end of the day, failure to adapt will result in no O2 at all due it becoming bankrupt.