Sprint changed their minds mid-stream. Just as the first LTE sites were being completed. Sprint intended to, from the beginning, to allow LTE sites to be discoverable to customers who had LTE devices and were within range of a completed LTE site.
However, around the end of April, they changed their mind and requested their OEM's to come up with a way to block Sprint LTE devices from connecting to the LTE network. They discussed several options and selected the best solution to implement.
It was a last minute and hasty decision to block LTE. And it has nothing to do with the network and being ready. It's about a device issue that Sprint doesn't want discovered. It would be figured out in two days if they allow their LTE network to go live.
Robert