I find the sound system to be more compelling than the projection system.

The audio amplification in some IMAX venues are rated for more power consumption than their projector lamp. 15kW across 12 channels in some cases. You could never recreate this part of the experience at home. The power you could replicate but not the acoustics of a gigantic auditorium combined with that power. You can get 20hz floor shaking in small parts of your living room where the standing waves build up, but at imax it works smoothly across every seat.