Going to the movies is a social activity. Sometimes people just want to get out of the house.
Still, as the interactive aspect ramps up (where you can "watch together" virtually (VR, or alternative), this will be less of a concern.
As for the part about "getting out of the house" there are lots of other things people can do for that, walk the dog, go to the caffe, "get some milk" at the grocer's, drop by the pub, etc.
In fact someone can even say "there isn't a compelling reason for leaving the comfort of one's abode to go get a beer in a shared space next to strangers who might behave very annoyingly. Plus there is getting there, the grime on seats, the crowds, etc." to your suggestion.