I cannot see how it costs as much to operate online as it does a store.
I was comparing A shop with A website.
The shop itself - online = warehouse
Shop Staff - customer service teams, warehouse staff
mechanics - graphic designers and web programmers (or spend on outsourcing)
Bills - affects both.
What the online business saves in not needing a premier location that a shop would goes straight in the extra wages needed for IT bods, SEO work and google adwords etc.
When you look into it there is actually very little difference.
(i'm not talking about bedroom sellers, but businesses that are there to make money and pay staff)
The main reason internet sites can afford the smaller margins is more in larger target audience than less overheads.