It's because the stages are too long, too much gaps every single stage and especially for PS. This stage should be short so literally everyone would go on nail there. Also it would be logistically easier, there could be better live streaming, probably better athmosphere with fans...

Next year with new rules having WRC27 and Rally2 cars competing directly side by side we can only expect there will be way more competition, and I don't see any other way to show them all on live (9-10 can easily increase to over 20 with both classes).