Yes but I don't want to type my billing details every time I need some thing. I don't want to wait 6 weeks. I don't know if other sites are reputable. I don't want to pay shipping. I like being able to wishlist stuff or store stuff in my cart for later and read lots of reviews on products (I'm aware many are fake).
There's also the fact that nearly every website runs on AWS, so even if I boycott Amazon (I'm sure they'll miss my $100 a month in purchases), I'm still providing them money by visiting the sites that are hosted on AWS. Pretty hard to completely avoid them in this day and age.