I agree with kurt that Sony's own systems (BetaMax, MiniDisc, etc) is Sony's own Achilles heel.
Whoa, whoa...
That's a big misconception. Blu-Ray is not Sony... at least not entirely. It belongs to at least 170 different companies. Yes, that many!
A large number of companies including Samsung, LG, Phillips, Lite-On, Mitsubishi, Panasonic, Pioneer, Sharp, AMEX, Hitachi, JVC, Yamaha, Zenith, BenQ, HP, Fujifilm, Imation, Maxell, Memorex, Optodisc, Ricoh, Ritek, TDK, Verbatim and many more. They already have a bunch of Blu-Ray recorders out on the market.
BetaMax failed because Sony owned it and refused to share it with anybody. That was 30 years ago. They learned their lesson.
Keep in mind that Sony and several companies listed above were involved with the development of the DVD format. This is also the case with Blu-Ray. Sony didn't just "develop" Blu-Ray, it was developed by the Blu-Ray Disc Association, a joint development team.
Sony is not keeping Blu-Ray to itself. They don't own all of it, it's owned by the Blu-Ray Association formed by several giant corporations. The key to the survival of a media format is the majority of studios backing it up. Blu-Ray has more studios backing them up as exclusive distributors than they do on HD-DVD. Buena Vista (Disney, Touchstone, etc), Fox, Lionsgate and more.
7 of the 8 major studios support Blu-Ray while only 3 support HD-DVD. I can see where they're at a disadvantage. It's a bigger problem for HD-DVD as they only have one exclusive distributor which is Universal. The other 2 are supporting both formats.
Not only that, Blu-Ray is much more capable than HD-DVD ever will be. Blu-Ray is believed to be capable of maxing out at 200GB with 8 layers while HD-DVD will only max out at 60GB.
HD-DVD and Blu-Ray have shown pretty much the same video quality for now... but that may change in the future as they expand.