As I work with a network provider, M2M not cellular, but still carried over cell and sat networks, it actually costs a lot more to provide for text than voice BUT the transmission of a text message costs more than the transmission of a phone call. Overall, texting is more expensive even though voice requires more bandwidth. However, the actual cost per message is still far lower than their fees of course, I wouldn't expect them to break even, they are in a FOR profit business after all. Providers look at the big picture, the number of people who have a text plan and don't use it helps to cover those who use a lot of texts.
During the mid 80's a similar issue got REALLY ugly between Telcos during long distance deregulation in the USA. The government eventually stepped in and tried to regulate but it was too far gone by then, capitalism gone bad. It's not always a bad thing to have government regulation, people take it way too far sometimes. In short, companies aren't supposed to subsidize one portion of their business (cellular voice for example) with another (such as text). They just rely on overselling user plans so that most don't get used. Unfortunately, due to demographics, they usually charge an elderly lady who needs a phone for safety. She pays a monthly fee and gets some free text which goes unused and covers the cost of some snot nosed punk who wants to sextext people in school. oooh, carrful, I feel a rant coming on, better curb it.
That said though, if you consider technology and efficiency, text is hip and trendy but is really moving back in time as far as technology is concerned. Maybe next year they'll reinvent the teletype too! Of course there is value for many, with tweets and likes, but that doesn't bear enough weight to make phone calls obsolete. It is 150% due to stupid consumers, mainly teens, and big fat marketing pockets.
As I've said too many times to recount, consumers are way too easy to sell to. They will buy whatever someone wants to sell them, whether needed or not. Just look at the crap people buy online, making complete idiots with ancient, regurgitated patents into millionaires.
With North America, the USA especially, being such a consumer driver market, people flock here from all corners of the world to sell whatever they want because they can't sell in their own country. If you tell people they need something, they will buy it, doesn't matter what it is. America is their land of opportunity because people are so bleeding stupid when it comes to spending their money.
What's the ROI when you invest in your kid's phone and text plan?
Compare that with TCO and there is no possible hope to build any kind of viable plan around it, it's a loss from day one.
What's the ROI on a Swiffer sweeper, for the owner of a swiffer sweeper? 1.6 minutes a day and a roll of paper towels every 6 weeks., But go to any fair or turn on any infomercial and Swiffers FLY off the shelves as people pay admission just to go and buy one.
K-Tel, Ronco and others have proven it decades ago, now it's become even worse due to an even more market driven, trend based society.
We simply live in the land of the world's dumbest consumer. Face it, mankind just isn't too bright at all.