What are you basing this on? Amazon (Prime) customers are way more wealthier than Walmart customers:
https://fortunedotcom.files.wordpress.com/2015/12/screen-sho...
Aesthetically perhaps, but it seems very well designed in terms of making purchasing painless, which is part of the reason Amazon do so well.
I do try to avoid buying things on Amazon now though, they've gotten too big, it's a little scary how much influence they have on online retail.