One of the main ways for the new breed of Mobile-first TV services to take off is for their operators to buy up rights to sports events. That’s the strategy that Verizon has underscored this week, adding the National Basketball Association mobile rights to those that it acquired for NFL football. It has therefore secured two of the three big US sports franchises. The other is Major League Baseball, which has an over-the-top operation of its own. In 2013 Verizon Wireless agreed to pay $1bn for four years’ worth of rights to a collection of popular NFL games delivered to smartphones. During 2014 the NFL started showing Sunday afternoon games on those smartphones. Now Verizon and the NBA have announced…