Pro vs Consumer
That is the main difference here, not the licensing costs of the Blu-Ray format. Pro users want the capability to have lots of audio/video data to use on their machines and to be able to share it around amongst each other. For this they have firewire drives, network drives at work etc etc etc, and the macbookpro still has firewire 800, as does the macpro and the imac. Yes there may be some that want to archive it to Blu-Ray or want to ship something to a customer in Blu-Ray format - but media shops will have some kind of external functionality to do that, and those will be few in number.
Consumers want to watch Blu-Ray/HD movies. So Apple has made their choice for them. Consumers cannot buy an HD movie in a physical format, which they can watch a year from now or however frequently between, share with their friends, sell on to someone else. Instead, everyone is forced down the route of buying another piece of kit (apple-tv) and then "renting" films, which if they feel like watching again six months from now...they have to "rent" again.
If you have an HD-TV, live in a fast broadband area and can get fast broadband (don't forget the market in Europe, Asia, and soon US is going to get multi-megabit downloads via Fibre....Virgin UK) queue-time will hopefully be removed as an issue. You then buy an apple-tv device, connect it to your router, and can watch things on your tv or on your laptop over their N-speed wireless etc etc etc.
Apple is trying to do with the consumer macs, what is has successfully done with consumer ipods, create and dominate in content delivery to consumers. They are ahead of the game in simple-to-use devices in this respect. It's better to sell tens of thousands of devices which then enable you to get extra revenue from consumers by selling them value-add services - like movie rental - than it is to maybe sell a few thousand more macs based purely on the fact they have Blu-ray. Let's face it, no-one is going to buy a mac because it has a blu-ray player are they?
In this way, they create and extend the market for music, movies, and more all delivered through iTunes/apple-tv interfaces. Then when mass-market adoption of movie rental over net becomes a reality, they can say they have the most integrated mechanism for delivering it...at which point they will probably bung a new 100GB version of Blu-ray writer in their machine so that the consumer can "own" the content - same as they do with putting music onto CD now via itunes.
It's all about the long game for apple, create the content and they will come to the platform!!