Adapting = Ruining?

I just noticed in this article that NBC is "adapting" The Office for TV in America. Why do they have to "adapt" it? They "adapted" Coupling this year, and it failed miserably, it simply wasn't as funny as the British version, and I'm sure they'll wind up doing the same thing to The Office, which is hilariously funny as it is. If you're a Netflix user, make sure to add it to your queue, you'll enjoy it quite a bit. So why can't NBC just get the rights to air the British version? Why mess with success?