It made the telco's point as well... the facilities necessary to keep a cell tower (much less *all* of them) operational until the grid is restored would be *cough* extreme. (sizing the generator to the site, the cost of MANY generators, quite sizable amount of on-site fuel, security to keep people from stealing it, and contracts to manage filling/cycling the fuel.)
Keeping CO's powered is trivial by comparison. There aren't as many of them. And many (almost all?) are manned sites -- techs work from there or are in there regularly.