Correct.
They are not going to let people route SYD-PER-LHR rather than SYD-DXB (soon to be SIN again)-LHR thereby allowing you to say book a DONE4 rather than DONE5 and save thousands.
The flight is by definition an ultra long-haul segment and sells at a premium. The rules will undoubtedly continue to reflect this.
As noted above for the last few years SYD/MEL-DXB-LHR have not stopped in Asia (as DXB is in Europe/MiddleEast) yet they have still been deemed to touch that continent. The only difference is PER-LHR won't stop at all.