Difference in looking at things, I guess. Personally, I won't buy a dedicated HD player at all, partially because I hate dedicated players (had a dedicated DVD player until the PS2, then never again), but also because I'd hate to spend money on one of the two players at this point in the chance that one or the other is killed off.
The only reason I have any Blu-ray movies at this point is because I have a PS3, and Blu-ray was a bonus to getting hardware I already would have purchased. I've actually spent money on three movies, during the $10 Fry's sale, but if HD-DVD comes out the victor, I'm going to hate myself for having done so. If HD-DVD is crowned the high-def media format of choice, then I want my ENTIRE library in HD-DVD - so, to me, those Blu-ray discs I already own are totally worthless.
I absolutely, positively do not want to have a situation where I have to use multiple pieces of hardware depending on what movie I want to watch. (I already have to do that every now and then when I play the odd import DVD that I own that isn't region free, and I despise it.) When I switched over to DVD, I completely dumped my VHS collection - I wanted nothing to do with it anymore. I'm not quite going to do the same for high-def media, because DVD will play in the same machine my HD media will, but otherwise I just won't go dual format. I can't stand the idea.
(Of course, it's funny, because I have all three of the current gaming systems, so obviously I don't feel that way about video games.)