If enforcing every console is online comes at the cost of half the potential console owners (if 50% don't buy the console because it phones home every 24 hours), it doesn't make any difference. 50% of 40 million consoles == 100% of 20 million consoles. We can all guess whatever figures to make whatever arguments, but the companies have enough real data to know what percentage of consoles are connected to the internet, and enough publishers are choosing to make online only games (effectively in some cases, with short offline campaigns) that it can't be a problem, and proportion of offline consoles will surely decrease over time as the world and users become more internetted in general.
Regardless if you have 20 or 40 million console users, most devs will almost always target the entire userbase. If a dev is willing to target a console with userbase of 20 million doesn't mean they would readily target just half the userbase in a reality where that console had 40 million users.
This wasn't about a handful of online titles. It was about encouraging online as a standard across XB1 development.