Looking at turnover alone can be misleading. Lets not forget that 3 has had to rollout an entire 3G network on its own using a high frequency (requiring more masts, but to be fair it didn't put that many up) and they have a relatively small customer base.
Also don't forget that 3 was fairly rubbish until 2007 when MBNL was formed so 3 could share T-Mobile's 2G mast sites and they could both grow 3G coverage.
They will need significant investment to rollout 4G and given their heavy investment in superfast 3G it seems pointless rolling out LTE on a fast scale. They need to see a return on the 3G equipment.
and they need 3G coverage as well as LTE to handle voice calls, whereas the other companies can fall back to 2G. Given the 2100mhz coverage issue, this is probably taking a LOT longer to plan.
o2 has taken a clever decision to use low frequency LTE which means less infrastructure required. This will benefit o2 greatly as they have plenty of debt already so keeping this to a minimal during the 4G rollout is the best way forward. o2 will get a good indoor coverage with much less masts than the competition.
Essentially they're all doing this, O2, Voda, and EE all have 800mhz, but O2 is the only one with the minimum coverage requirement. Voda has the 'biggest' slice of spectrum at 800mhz - but EE has physically more spectrum at 1800mhz. What this means in the future is unclear!
EE already has more cells than Voda or O2 as they had to compensate for 1800 versus 900 in the old 2G days - so perhaps Voda & O2 will end up with similar coverage to EE but half the capable speeds, due to more people per cell site, as the cell sites will be bigger.
Something to watch
James BT Infinity 2
19/09/2012 - Sold 42/6 - Getting 46/8 - Sync 50 / 9 Mbps @ 470m approx
14 years of broadband (ntl: cable to BT FTTC) - Router: Asus RT-N66U - Modem: Huawei HG612 speedtest