During 2015 American AAdvantage gave a boost towards elite status to members buying premium fares in the form of an ‘elite qualifying points’ bonus.
United, much more known to ‘manage by doing what Delta does’ has gone ahead and matched American’s bonus qualifying miles structure for premium fares for travel in 2016.
They aren’t doing anything to make earning elite status harder on low fares (United already has minimum spending requirements for elite status, American will not have that requirement).
Instead they’re making it easier to earn status quickly for folks buying paid premium cabin fares. This will also likely mean more elites and more higher-level elites than before.
At American they expect the number of elites to stay constant, since higher premium cabin status miles earning comes as the ‘qualifying points promotion ends. They’ve already inflated the elite ranks somewhat so won’t be doing it further with the new bonus. United will be, at least relative to 2015, as they match American’s efforts.