The problem is digital distribution will never take off unless people let go of their optical drives. People are very stubborn when it comes to change.
Using the oft quoted Ford line "If I had asked my customers what they wanted, they would have said a faster horse."
This is why the PC industry has been so stagnant. PC makers just give people what they want without any thought to progressing technology as a whole.
This is also what makes Apple so popular or unpopular, depending on what side you're on. They are very quick to take away technology they feel isn't the way of the future. Floppy drive, Flash, etc. People hate them for it but in the long run, it forces technology to advance.
EDIT: Just to expand on this, a lot of people call Apple greedy but they take HUGE financial risks for things they believe in. IIRC, Apple had been losing money on their iTunes music store until very recently. The idea that anyone would pay for music online when it was widely available for free was absurd and the cost to set up the infrastructure of their store was huge. Because of their gamble, they single-handedly saved the music industry. Can they do the same for movies? If there is demand. But they cannot afford to offer high bit rate 1080p video until there is enough demand.
This has indeed been a tactic of Apple in the past, and it still is to some extent (you correctly point to the iPad's lack of Flash). However, it's simply not applicable to this Blu-Ray-situation. The Floppy-less iMac and the Flash-less iPad were pretty bold business decisions that infuriated some people but are actually based on rational reasons. In both cases, Apple, like some benevolent dictator, tried to nudge its customers towards a newer, better or more open standard. With the iMac, this gamble obviously paid off - it remains to be seen whether it will work out for the iPad, but at least you can support both decisions with valid arguments. In both cases, Apple is withholding something for good reasons, and in the case of the iMac, they simply provided a better alternative (a CD-drive).
When it comes to Blu-Ray, the situation is different. Here, Apple is withholding what is actually the current standard for optical media; they are withholding the latest and greatest, which they have not done before. The Floppy and Flash are/were things that were dying or should have died a long time ago. Everyone realizes this. Blu-Ray is actually a great technology, it's state-of-the-art, it's the current standard, and it's not going to go away for at least a few years.
And another thing that's different this time: Apple is withholding something without offering a better alternative (e.g. the iMac's CD-drive) or at least a vision of a better alternative (e.g. HTML5 for the iPad). Again, they're simply withholding current technology and forcing their customers to settle for obsolete or inferior technology (the Superdrive or iTunes downloads). That's infuriating! If Apple's stance on Blu-Ray were actually comparable to their stance on Flash or Floppies as you theorize, they should be a lot more radical. If they're serious about abandoning optical drives and media, they should simply DO IT ALREADY and start offering laptops without these drives and start selling digital media at 1080p all over the world. That would be a believable strategy. Instead, they're still offering downloads at terrible quality and they're still including the obsolete technology in their Macs (Superdrive) and pretending that there's nothing better around. And now you're telling me that customers should give them an incentive to offer something better by downloading lots and lots of movies and making the iTunes store (more) profitable? Hell no. I'm fine with Apple not giving me everything I want, but if they decide to omit the current standard for optical media from their computers, they had better be ready and willing to provide an alternative. They're not. Realize this: it was easy to wean customers off the Floppy drive, because there was a superior CD-drive in every iMac. They realized Apple's point as soon as they turned on the iMac. Apple might even be able to wean customers and content-creators off Flash, since their arguments against Flash are valid. But how are they going to get us to let go of optical media when they are only half-heartedly offering a vastly inferior alternative to only one set of their customers (Americans), while still building obsolete Superdrives into all of their Macs? If there's a strategy behind that, it's not comparable to the "no-Floppy"-move. It's stupid.
So really, this is not the same thing as Apple's expediting the death of the Floppy or their understandable attempt to kill flash. This is like releasing the iMac with a ZIP-drive instead of a floppy drive and calling CD-ROMs a "bag of hurt". Or keeping the Floppy around while offering stripped-down inferior downloads of CD-ROM-content, all the while pretending CD-ROMs don't exist. They are once again withholding something from their customers, but this time they have no valid reason to do so and are not offering any viable alternatives to the thing they're withholding. It's a massive blunder, as I said before.