Ah you are correct. But that one word you did not initially say "mobile" makes all the difference. But in the mobile world you are totally correct. Maybe everyone knows what 7 and 10.9 is and Apple needs to say nothing more on the billboards there. Everyone who paid the $1500 knows Apple's 2x OS's are going to be updated soon. I think Apple is targeting the attendees and not the outside world (ie us watching the keynote) with them. But in saying that many people would understand what 7 and 10.9 means in relation to Apple as well.
