I used the Amazon tool recently to get a very particular type of screw. It was really easy to find exactly what I wanted.

Then I still got the wrong part delivered. It doesn’t matter how great the selection tool is, the rule is always: garbage in, garbage out.

I think it's the same as the overall enshitification of all products and product quality. Consumers now value cheap fast shipping and low prices over everything else. Amazon delivers that, with the tradeoffs in product quality, support, etc. Other things are low quality too, like the product listings themselves. Often, for example, the listed dimensions or other specs (thread type, grade strength, etc) are missing or just wrong. That's much less true for sites like McMaster. But nobody values that anymore.