Also to back up what Kosty said, over 90% of Blu-Ray hardware sales come from the PlayStation 3. There's been plenty of great analysis about this by sites like Arstechnica and others, and they've mentioned that game console adoption tends to be much faster than most other electronics. In other words, if it wasn't for the PS3, the Blu-Ray camp wouldn't have anywhere near the advantage they currently enjoy. Standalone HD-DVD player sales outnumber standalone BR player sales by approximately 5-to-1.
So, if Wal-Mart floods the market with extremely cheap, even *halfway* reliable HD-DVD players, it will most likely offset the edge PS3s give to the Blu-Ray camp. Two million+ $199-$299 (or cheaper) HD-DVD players available from the world's largest retailer versus a $599 PS3... Yeah, I know which one I'll be buying for movie watching.
And once the studios see that, they won't want to lose out on such a big revenue stream... You'll see more HD-DVD discs released, more big titles, more support.
Whatever the case, if I were Blu-Ray, I'd be at least *slightly* concerned...