By that logic, Macs wouldn't have DVD drives either since they can be used for playing CDs and DVDs, which can be bought on iTunes.
Except for two things:
1) CDs widely predated iTunes
2) They are still used for other methods like software distribution - distribution that doesnt work digitally.
None of these applies to Blu-Ray which is limited to movies.
Hell I would have been happy if they'd just gone with normal size display port which is becoming the new standard on corporate issue laptops, and actually making some headway at replacing VGA on boardroom projectors.
But no, instead they have to come out with another obscure port.
I believe that VESA was looking for a compact version of DisplayPort already but I cant say that for sure...