It will still be here, it's going to take a lot longer for physical to go completely. Digital is at what... 35% now? When it's at 85%+ then we can talk about physical disappearing. Though you might start getting some specific games going the digital only route sometime next-gen.
LTD: PS4 - 125m, Switch - 110m, XBO - 51m
2020: PS4 - 9m, Switch - 22.5m, XBO - 2.5m, PS5 - 4.5m, XBX - 2.8m