I'm trying to relate the cases to my own experience.
With my CTS-HND/NRT-HKG example, JL (as operating carrier) rescheduled (well in advance of departure date), but CX felt obligated to assist. So I cannot agree with your assertion "If Emirates changes its schedules and creates an invalid connection time in the schedule them Emirates should rebook automatically". Unless CX and QF's CoCs are drastically different.
OP isn't exactly the same as my case though - he has IRROP affecting estimated departure not scheduled departure. But still some time ahead of the commencement of his journey. Ticketing airline's problem or operating carrier's problem?