On-line sales will remain low as long as delivery will take more time than reaching the shop around the corner. Uber starts crowdsourced Home delivery with Food because it remains the same day delivery' s Model. No stocks and on-demand production make it simple.
It is another story when you have stocks.
Then the option is to get on-line the real time picture of stocks in stores and pîck up your order there. It happens for some non-food business where stock management is strictly followed-up. House ware and High tech products for instance. The same day delivery may then be more the same HOUR delivery. If UBER provides the tools to all shops around the corner, then they will change the e-commerce lanscape as the shops around the corner.