[yokohama11]

Most large companies do/have done exactly that. Arguably 9/11 was the big catalyst for DR planning.

There were Wall St firms that literally had to get the military to escort them into Lower Manhattan in the days after to rescue servers, tapes, etc and cobble something together in a satellite office.

No one wants a repeat of that, and you'll notice subsequent disasters like Sandy have barely been a blip for most as a result of policy changes.

At this point basically any major company will/should have procedures in place for "perfect" DR, the ability for everyone to work from home indefinitely (and alternate offices/infrastructure waiting for the few people who need something special, like the special needs of a trading desk), as well as obviously having back up data centers with full replication.