What about input and display devices? Although school can afford buying some cheap keyboards, the displays are much more expensive and it's pretty hard to work without them.
Installing programming tools on whatever PC the parents may have is not a reliable, trivial, or consistent process. Parents will be upset if it somehow the installation screws up the home computer.
And yes, for some households with limited income, they may have enough money for an HDTV _or_ a PC, but not both - and most households will have opted for the HDTV before the need for an adequate PC for classwork became an issue.
You've understated this point. Kids should be encouraged to (educationally) do things that will screw up their computers, like attempting to build their own kernel. They shouldn't have to worry about getting beaten because mom can't play Farmville after they've been experimenting.
Yeah, that'll go over well.
Spend the $25 on a do-what-you-want-to-it R-pi already.
I'd suspect for those for whom it is genuinely a choice they could opt for a second hand TV and second hand PC instead and afford both. Getting hold of a PC if you really want one seems to be quite easy, even in my poor city¹ (we have things like shampoo on our Freecycle, I kid you not, single bottle) there are quite a few opportunities to get a full computer for free ... but you'll have to accept an old model (oh noes!).
That said how does this all fit in to the stats I keep seeing that say computer use in school doesn't improve grades.
Would love me some RaspberryPi however.
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1 - relative to the wealthy developed country I live in
Unless those grades are in computing, they aren't really relevant to this project.
2010 HDTV US home penetration: 65% [1]
2006 PC US home penetration: 73% [2]
[1] http://www.bizjournals.com/washington/stories/2010/05/03/dai...
[2] http://www.zdnet.com/blog/itfacts/us-pc-penetration-is-at-73...
2) As also noted below, the goal of this project is to produce a computer for children to learn about the computer itself. The low cost (presuming the parents are even buying it directly) means kids will be able to have their way with it without worrying about wrecking the family computer.