Like lotsofpulp said, Walmart makes it quite easy to filter out 3rd party sellers. But with Amazon this is sometimes impossible because of fulfilled by Amazon and commingling of skus.
I’ve also found it useful to limit to only what’s available in my local Walmart.
Walmart isn’t perfect but their quality control is much higher. Oddly, their customer support is much better too. The last few times with Amazon the rep was like pulling teeth. They once asked me to mail back a $10 item so they could review its quality. It’s just a hassle that Id like to avoid by working with higher quality retailers.
I don’t think it’s a consumer cost issue either as Amazon isn’t cheapest. I think it’s just where they are choosing to make their money and they’ve shifted from innovation and market capture to rent seeking.
Walmart is garbage for the same reason as Amazon. Unmoderated third-party sellers.