Originally Posted by binary:
“A 4G base layer that doesn't support voice 'out of the box'.”
You're missing the point really.
By the time 5G arrives the control layer will still be LTE and the 5G will effectively be a massive amount of bandwidth dynamically CAed onto the 4G meaning that the average consumer on a day to day basis has no idea what RAT they're using.
By that time every 4G network in the UK will have VoLTE deployed properly and optimised so that's not an issue.
Yet it's annoying it didn't ship with LTE and it is a bit of a f*** up but at the same time it's not utterly surprising. The switch from circuit switched to packed switched voice was always going to be difficult and torturous (much like some of the earlier posts in this thread). The amount of optimisation and ball ache required for VoLTE means that in general it's been better to wait until an operator has deployed large contiguous amounts of LTE before they activate it. That's why EE said that they'd wait until 90% Pop coverage until VoLTE and why they were about 95% when they actually launched it. Even if it were available from launch there's no guarantee it would have been used.
The issue in my mind with VoLTE isn't the timing it's the availability of configuration for devices due to a lack of a standardised implementation - that is the real f*** up.