Many users overseas think they have "unlimited free incoming calls". Many choose to ignore they are hooribly expensive. The cost, though, doesn't show on their cell bill. It shows up on their home or office bills.
Your statement about the early popularity of SMS in Europe is definitely true. Now that SMS is popular in the U.S. - all the carriers have raised rates, significantly. It is a real cash cow for them now. You can send and receive unlimited amounts of data via email and web browsing for about $25. I think most carriers now charge $10-$15 for unlimited SMS where only a minuscule amount of data is involved - even if you are a kid doing 100/day!
I added a 400 SMS pkg to my plan for $5 last month because, now, even businesses are making some use of it. For the 3 or 4 a month I was getting, 20 cents each was fine. Now i'm getting a couple a day and even sending a few each month. Airlines have been using it for awhile to let you know the latest info about delays etc.
More and more business types are using their cell as the primary means of communication here. You couldn't do that in the rest of the world where it costs 15 cents/min to call a cell number.
Make use of T-M's UMA/wifi free calling from any place in the world with access to wifi. Wife uses HTC Android that has a form of UMA wifi calling. I use BB 9700, which is fully UMA capable.
U.S. T-Mobile unlimited minutes (incoming and outgoing), 2GB data each line, unlimited SMS for 2 lines - about $140/mo. for both lines line. (In U.S. no surcharge for calling a cell.)