"When the power grid goes down, the internet, cell towers and repeaters won't do us much good."
Yes and no. I have seen "the grid" go down after major hurricanes, and the cell towers were busy as all heck but cellular service stayed up 48 hours longer than the flooded and fallen phone lines. These days, that means internet service will probably be up as well.
"The internet" is a global physical network, IT doesn't go down unless the planet blows up. Your local access will go down from time to time. Your ISP will go down from time to time. But "the internet" is an incredibly large and robust device, which never has "gone down" in it's entirety.
The landlines aren't what they used to be. And part of the post-Katrina discussions resulted in cellco's making reciprocal arrangements, in many areas now whoever has whatever kind of fuel that is deployable, will deploy it to all towers from all carriers, And they've all invested substantial bucks in independent generator backup AT the towers.
Depnd on the internet? Hell no, no one in emcomm depends entirely on any one thing or person or organization. But "the internet" is an incredible tool and only a fool would make plans that didn't provide for using it, when they could. If your local access is down? For the price of a big screen TV you can buy an earth station and get satellite access. And yes, the satellite ISPs and some of the logistics companies have been stocking field-deployable emergency packs, just for that purpose.
Not the only tool, but a handy one to have.