why are people assuming that the cross class skills system will not be here for the new jobs ?

currently, jobs don't have cross skills because the only "job" skills are quest skills, which can't be "cross classed".

but if the start as jobs at level 1, they won't have only quest jobs, so they will be able to "cross class".

Also, the whole "class/job" is just semantics. "jobs" are advanced "classes". Or rather, "classes" are for levelling while "jobs" are for end game, which is why the new "jobs" are called "jobs", they'll have a use at end game.