Not capitalism as we know it, Jim
"Simple one-word answer: Capitalism."
Russell Brand has entered the room.
I think you will find that roaming charges are basically socialist.
The charges fall on the wealthiest, who expense them to their employer (amortising the cost over a business), and generally fall on people who can afford to travel. The profits from roaming charges keep prepay PAYG prices down, keeping costs down for people who tend to be the poorest. Your definition of capitalism is therefore "the rich subsidising the poor" - which will be news to most people.
Of course understanding this requires you to think a bit, rather than give moronic one word answers.
When roaming charges were introduced the tariffs for the poor went up. Another EU triumph, but one that leaves bureaucrats (who roam a lot) very happy. Trebles all round.