Actually...HD-DVD hasn't made hardly any money...players are sold at a loss (like the PS3 will be), and even worse, software isn't making hardly any money. Whereas, Blu-ray software (at the same price on average as HD-DVD software mind you) has been profitable out the gate.
There's more software for HD DVD out there currently but no one's making any money off of it...less Blu-ray out now but it rakes in cash...which do you think the studios will stick with? Once PS3 hits...who knows.
HD DVD is nice...a really nice product...but I don't see how it would "win" the format war with less studio support, those studios practically giving the discs away (yet still having to pay royalties and licensing to DVD forum), and the OE hardware also not making much of a margin.
And the 360's HD DVD Add on? MS could care less if either side wins actually...they are the ones making money off of VC-1 (HD-DVD's main codec and also a Blu-ray codec as well).