I think A9 still exists as a search subsidiary, it's just that the consumer-facing portions were discontinued. A lot of A9 alumni now hold leadership positions in Google Search.
There's truth in this. Generally, I search for part numbers on google or rockauto, and then you can find them on amazon. The UX for finding parts that fit your car on amazon is either confusing or broken, I'm not sure which.
Both. This may because of the existing parts distribution system already in place. It doesn't see to be a place they have been putting much effort into. There wasn't even auto part search until recently.
Last I checked, it's impossible to do a useful "sort by price" for many items. I was looking for...I think it was a 3.5mm audio splitter, and I wanted to find the cheapest one. Searching by relevance mostly returned 3.5mm audio splitters, but dozens and dozens in no particular order. Searching by price returned every single thing in the database with "splitter," "audio," or "3.5mm" in the name or description. Frustrating.
I tried to reproduce this result. After searching "Nexus 7 bluetooth keyboard case", I got a page full of relevant results. I could get to a page full of awful results by first selecting a department, then sorting by average rating.