In my experience there is little difference between weekdays and weekends. I stopped bothering with bus long time ago & simply walk, takes less than 2 hrs. But this is probably not an option for everyone. Also 11 (x2) km spent walking saps some energy better spent exploring the alpine.
I'd consider eliminating bus completely and allow cycling on the road instead. In reality it would NOT open flood gates as tourons are not likely to cycle up 11km with >300m elev. gain; if anything it would further reduce human impact on this iconic area. It would also put less strain on campground as you'd know you have to either walk 11km or cycle with heavy overnight pack. And if they wanted to be really smart, they could try selling say 2 buses per day, with some ridiculous ticket price, 200$ or more. There would be deep pockets willing to pay just to sit with tripod by the lake. Just as somebody is willing to fork 400$ or more for night at these O'Hara cabins. Money from proceeds could then go to back-country facility maintenance which does not exist at all nowdays as all funds are going to Johnston Canyon railings etc while things like Suspension Bridge over Athabasca on Fortress Lake trail or Peyto creek crossing on Caldron Lake approach will never be fixed as it seems
Yeah I don't care about the bus, I want the campsite, I want 3 nights. They should completely get rid of the bus and make it a 100% backcountry lite destination. For the $400/night huts, for the campsites, and for the ACC hut. Without all the bus day trippers they could double the capacity of the campground or build another one. Everything would still sell out anyways..