$6.5B is just the first part of it. From the article:
> AT&T's contract with FirstNet is 25 years long. "AT&T will spend about $40 billion over the life of the contract to build, deploy, operate and maintain the network...
That's what I'm thinking too. They are probably going to feature a couple of notable big-press dig hole events and show some equipment, but in the end this is a set of code changes and specialized devices that will emit a new code that gets special priority. Total cost to AT&T: a few million. We all paid taxes for that..
More like a few billion. A few million dollars is nothing in telecom. They've almost certainly already spent at least that much just to bid on the project. The upgrades will include things like structural re-enforcement of towers, increased battery / generator capacity, security enhancements, etc.
That's assuming all their equipment supports 700mhz. They might need to add antennas, front circuitry etc. They also probably need to do a lot of testing to validate it works. All this is not cheap.
