I swear there's a hole in the market here. A third option that was online-only with collection points/delivery services similar to Colesworth that undercut on price.
Startup costs would be massive, though not as much as trying to enter the market as a third retailer with physical stores in all the suburbs.
It could start with a few distribution nodes (warehouses) and grow out. Order online, go to warehouse to collect. The next step where you can distribute in more suburbs or deliver to homes is where it gets most difficult.