Why not? In order for a format to become successful and prove itself someone has to buy it. By your logic, we should all be listening to transistor radios, watching heavy black and white tube televisions with rabbit ears, and still riding around in horse and buggy's. Technophiles feed the frenzy that creates an interest in a product.Blue Ray might win the HD format war, it may not. But would anybody who's smart about they're money want to spend a considerable amount on a format that hasn't proved itself?
Just because Sony's track record from proprietary products hasn't been the best doesn't mean BluRay will fail. Doesn't mean it will be the winner of this format paradigm either. Beta failed for a few reasons in the consumer market. It was bulkier and more restrictive. Sony is very strict about what companies can press on their media. VHS took a lead over Beta after the adult industry embraced it. Sony had banned the industry from selling porn in Beta format. That shouldn't be as big of a deal now as most adult content is now viewed and purchased online.
Back to my point, if no one spends "a considerable amount" on a new format, we are stuck with what we have. Currently it would be up to 14GB of storgage space on a disc.
Personally, I'm waiting for the disc to go away and hard drives take over. You can get 750GB hard drives for a fairly decent price right now, and that will continue to get better. It is the future, some cars already use a hard drive for mp3s and navigation systems.
Read the second to last paragraph. I know the nav system is a bit large, but its the start of the next big thing.