Bob,
I don't entirely disagree with your sentiments. There is definitely a tendency to confuse the value of content delivery with the content itself. And the appalling level of support for the public schools is a major concern of mine, as well. Though frankly, I fully support my daughter's elementary school not budgeting a dime for "typewriter ribbons" or "floppy disks."
By the same token, however, I think it's easy to toss around figures about the cost of technology without doing the arithmetic. Perhaps that's because some of us who went through school with slates and chalk didn't really "get" arithmetic. Consider the following scenario.
My daughter is in the first grade in a class of 24 students. Assume that the school purchases 12 iPads for the class at a total cost of say, $6000. Given the way her class is organized with groups of kids working on different subjects, topics, projects, etc. I don't think it makes sense to have an iPad for every student but a single iPad for every two kids does, I think, make sense. Now let us assume that the iPads have a (conservative) life span of three years. That would mean that 72 kids could be served over the life span of the iPads. $6000/72 = $83 per student per year.
Now $83 is a significant amount of money to spend if the only value is a "cool" device. But that hasn't been my experience with my daughter. Her class is studying planetary systems at the moment. I've found both the NASA app and the Moon HD have been extremely valuable in enabling her to supplement her classroom experience in those areas. And that's only the tip of the iceberg. Electronic books, math exercises, and a wealth of other educational content is available is available at less cost than providing those same resources in "hard copy" form. Furthermore, I can only speak for my daughter's school (where her mother and I are frequently in the classroom) but I can assure you that her teacher would be aware of her students playing "Angry Birds" rather than doing productive work. And it wouldn't last long if it occurred at all.
In short, I'd strongly support adding iPads to my daughter's classroom. (The class currently has three aging laptops shared by the students.) I'd be more than happy to contribute $83 per year to enable all the students in her class to have access to the content the iPad can deliver. And I have a lot of faith in my daughter's teacher to make good decisions about how that technology's value can be optimized to meet her student's needs.