You don’t buy things from Amazon because they’re the best store with the best prices, you buy them because they’re the only store that has their own massive scale delivery service that delivers more packages than FedEx or UPS (not combined, but Amazon still delivers more packages than either).
It’s not possible for another store to compete with that. There is no competition. Starting a competitor to Amazon would be more difficult and capital intensive than starting a new car or rocket company.
There is no other store that can get me the most obscure and random stuff in less than 24 hours. Walmart can’t do it, Costco can’t do it, Target can’t do it, Dollar General can’t do it.