Come on, Microsoft obviously knows that the traffic is going to spike significantly, but they simply don't care enough to spend the $$$ necessary to upgrade their servers.
Once you've bought the game, you're captive customers with no refunds on opened software. MS is smart and knows this.
Do you really think MS doesn't care how the first big release on next gen goes? Some people had trouble signing in and it was mostly new owners who picked up the system for TF who couldn't sign in. They had the problem sorted within 8 hours.
Titanfall is very cool.