To some people, it was odd that Blu-ray disc drives never made it onto a Mac system.
Apple had no trouble progressing through the early years of optical disc advancement. They sold CD-ROM and CD-RW drives on the original 1998 iMac (famously eschewing the floppy drive), introduced the ComboDrive that could read DVDs in 2000, and the SuperDrive that wrote DVDs in 2001.
One could have easily seen Apple introducing an "UltraDrive" at some point to handle HD discs (after paying Chrysler a bit of money for the name). At Macworld 2005, when Jobs declared it the year of HD video, he said he was anxiously awaiting a drive that would allow him to burn HD videos from iMovie.
The main impediment was a format war. HD-DVD was fighting Blu-ray for supremacy, and Apple was not going to introduce a drive that backed the wrong horse.
That format war ended in February 2008, with Toshiba throwing in the towel.
But that date was too late for Apple to get on board. Just one month earlier, Apple introduced the MacBook Air, which signalled their intent to abandon the optical drive entirely.
The confluence of product introductions that allowed this ball to start rolling is quite remarkable. With iTunes Movie Rentals and Time Capsule unveiled earlier that very keynote, Steve Jobs had a ready answer for people questioning the lack of an optical drive in the MacBook Air.
It was only a matter of time before product refreshes would gradually eliminate the optical drive from each new design. The Mac Mini in 2011, the retina MacBook Pro and iMac in 2012, the Mac Pro in 2013, and the MacBook in 2015. As of 2016, there's only a single Mac left with a SuperDrive: a 13" MacBook Pro that hasn't been updated since 2012.
If not for the format war, I think we would have seen the UltraDrive for a few years. But its days would have been numbered from the start.