The non-amazon shipped stuff on Amazon honestly had been a pain ever since they introduced it. If you have prime it mostly is just a huge nuisance.
Whereas if I'm in a brick-and-mortar store, I can at least evaluate the quality of something hands-on, and then have a better idea of if the cheapest is good enough. This is exacerbated by item descriptions that are frequently inaccurate, even showing the wrong photos. The third party sellers especially don't seem to be held accountable for much, and processing returns through them is often a disaster.
I fear that Amazon is creating damage to their brand by not establishing some minimum floor for product quality. Right now they rank somewhere between a dollar store and a Walmart in my mind.
I'm almost inclined to go prefer local stores again, as Amazon's pricing advantages seem to have slipped, and if they raise the cost of Prime again, I'm definitely out. I've been a pretty loyal customer to Amazon, but honestly, they're slipping a bit.
They should probably spend just a little more time on their core products.
Look, Amazon, you have a real problem with sorting and filtering. What I really want is a way to order goods by the final, bottom-line price, including all taxes and shipping costs. If something costs $20 plus $10 in shipping, it should rank after a similar thing that is $25 plus $0 shipping.
The Prime filter is the only way I can even approach that problem from my end. It forces the cost of shipping to be included in the price of all items, at the expense of not seeing potentially cheaper items. But even then, Amazon can't even manage to sort correctly by price. Nor does it handle quantities in a package very well.
It would be hard if they let you search by say < 3 business days, < 5 business days in the same way they let you search prime only.
I really don't want Amazon to turn into eBay or Alibaba, but for many categories it already is if you scroll/paginate far enough.
Given that it happened several times with several vendors, I suspect there's a systematic problem due to incentives - higher power bulbs command higher prices, and most buyers don't have the test equipment needed to detect the fraud; and even when someone does detect the fraud you just have to refund them and claim it was an accident.
Needless to say, if the conditions of the market mean that fraudsters out-compete honest sellers, all the honest sellers have to quit or resort to fraud, and the market becomes useless to consumers.
100% of the reason I use Amazon is fast and consistent shipping. That is the entire value for me.