Sprint is playing it smart with VoLTE - the reality is it isn't a technology that's fully reached maturity at this point, and there are a lot of other carriers (KT in South Korea, Softbank even in Japan) that are deploying that technology. That will allow Sprint to piggy back and use what they learn to make their own roll out a bit smoother. At the same time, I wouldn't take anything re: network operations that Sprint says right now as gospel, with all of the people leaving and with Son's management style, for all we know this might just become a priority again in a few months