First, the iPhone 3G plans don't have any text plans. That's at least $5 extra or 20 cents per message.
Then you go to the dumb phones without data plans, and you're then paying for whatever your texting plan is AND the data.
Yes, it is hard for me to understand the need to send people a photo RIGHT NOW RIGHT NOW RIGHT NOW. I have never ever ever taken a photo that I had to send to someone that instant. I just reject the whole lame notion that sending it via the MMS route should cost you a text message when a bloody e-mail attachment is free. I'm more mad at the joke of the xMS systems for raping people of their money, especially smart phone users. "You've got unlimited data, but that itty bitty two-word SMS you sent will be 20 cents."
Its hard for you to understand, as it is for me, because, as adults, we recognize that there is no such need, in any situation.
In fact, I can't think of anything more rude than clogging up someones text message space/bandwidth by sending them a picture, likely of something they couldn't care less about, or could have enjoyed just as much an hour later. In fact, text messaging has an urgency to it one small step below 'phone call', and to send a picture that way is like saying, "i need you to see this now!" Well, while that might have its once a year use, its mostly rude.
Both elements are at work here. Greedy carriers depending on stupid customers, and of course, stupid customers.
The "I can/cannot get MMS to work," threads are hilarious. I don't know if it works on any of my testing 3Gs, and if it did, I wouldn't know how to test it. I can't think of anyone I would "text" a picture to.
I can think of a few thousand I might e-mail though.