I read those tweets and felt the sheer contempt burning through the internet, as did many other people.
If the always-on thing is required for the Xbox720, effectively Microsoft are saying "we don't care if you can't use your product you purchased from us because of a hundred possible reasons". Moving house can mean a month of downtime to get internet connectivity back up, nope, can't play games during that month. Recently an Australian telephone exchange burned down in Warrnambool - the entire area had no internet connectivity for a few weeks - yep, no gaming during that time either. A tree took out my phone line and Telstra took 2 weeks to get it repaired - yep, no gaming during that time. These are just the examples I can quickly think of.
We currently own 67 Xbox 360 games in this house, and have two of the consoles (one for my wife and I and one for our kids). If having the internet permanently connected for the purposes of DRM is a requirement of the Xbox 720, I guarantee we will purchase exactly zero consoles and games for that generation.