Why would I put stock in when you have an obvious bias. If it makes you feel any better, I don't trust anything Steve Jobs says about Blu-Ray either since he also has an obvious bias against with iTunes/AppleTV trying to compete against it.
It's not just about "safely" delivering movies. It's also about delivering them in a practical manner. I think the last statistic I saw showed a U.S. broadband adoption rate of about 60%. Do you really think the studios want to drop disc formats and in the process lose at least 40% of their potential customers. And the term broadband covers all sorts of speeds so even the 768kbps/1.5Mbps DSL speeds still qualify as broadband and at those speeds a downloaded movie could take days to download.
Last time I checked, 1TB drives were averaging $100, so your 8TB system would currently cost around $800. And for all that money, what have you ended up with? Basically a bunch of empty shelves. For that much money, you could bury the axe and buy a Blu-Ray player and around 25 movies. Which seems like a better investment? But feel free to sit around and wait for those 2TB drives to come out and then wait even longer for them to be sold at affordable prices.
And it's also been shown that trying to compress a movie into that small a space has required downgrading video and/or audio quality (for example, the inability to fit a lossless audio track on the Transformers HD DVD even using a 30GB disc). And it seems like most HD DVD's came on 30GB discs so I'm not really sure how much stock I put in your 15GB comment.