Honestly I don't think a one-stop-shop can be unassailable. Having a depth/variety of products is important, not just for consumer's sensibilities but also for being able to cover all the use cases. A Walmart might be most of a grocery and pharmacy and toy store, and half of a garden and hardware and auto parts and home furnishings store, but it will never be all of all these things (and perhaps not even 100% of any of these things). The logistics just becomes prohibitive.
The businesses that are best to start with are the ones where online shopping is unsatisfactory.
Honestly I don't think a one-stop-shop can be unassailable. Having a depth/variety of products is important, not just for consumer's sensibilities but also for being able to cover all the use cases. A Walmart might be most of a grocery and pharmacy and toy store, and half of a garden and hardware and auto parts and home furnishings store, but it will never be all of all these things (and perhaps not even 100% of any of these things). The logistics just becomes prohibitive.
The businesses that are best to start with are the ones where online shopping is unsatisfactory.