I've always found examples like "couples sitting in a restaurant, ignoring each other in favor of their phones" as kind of hilariously judgemental. Almost in the same way that ignorant extroverts view introverts.

If they're a couple, why would they feel the need to always talk? You don't need to always be talking to enjoy just doing your own thing in each other's presence. Even prior to the proliferation of smartphones this was pretty normal in my experience, you spend most of your time having the ability to talk to the people you like, at some point you run out of things to say and are comfortable enough with each other to just do your own thing while in each other's company. It says nothing about their connection with each other.