Part of this has to do with the cost of Ubuntu. I'm not talking paying developers to make sure it works on the machine, but the actual cost that Canonical charges for the ability to use the Ubuntu logo and becoming "certified"; It's not a trivial amount of money by any stretch.

Anyone can preinstall Ubuntu on a machine and release it, they just can't say it is Ubuntu specifically or use the logos.

And I don't advocate not paying it or not becoming certified, we are considering it currently but I can say that management has balked a few times when we've brought it up has been due to the amount of money required up front.