Why No Kindle Cover?

I find it a bit strange that Amazon don’t supply a Kindle cover along with their reader. After all, they have had some problems associated with cracking screens which may well have been caused by non-proprietary covers. When you think about it, to supply a $10 or $20 cover with a device that costs $259 isn’t much to ask is it? Even if it wasn’t that great, they would cover (sorry - no pun intended) themselves from a legal viewpoint wouldn’t they? Anyway, it’s no big deal, there are plenty of independent suppliers who are more than happy to sell covers for the Kindle.