I had a discussion with a few mates not long ago that was similar to this, basically I remember a time when my parents wold take us shopping in a supermarket, they had someone on the till and someone else packing the shopping. Over time the person doing the packing was lost, they then introduced self service check outs to reduce the labour cost of the check out people. Move forward to today and they realise that they need people to service the self checkout machines and so are now pushing the online shopping angle.
The chase for maximising profits will only end one way. The supermarkets themselves are now the biggest costs and they will seek to close them down. They will maybe convert a couple to huge collection depots but the world we live in is going to change drastically.