Because all the smart people at Google who worked on Quality (Ads Quality, Search Quality, etc) got promoted and moved away from those, and the revenue is good enough that google can maintain its monopoly without improving the product.

This is laughable. This isn't incompetence.

The system was never designed to show you relevant ads that you want to see and would like to buy a product from. The system has always been designed to show you profitable ads. Those have always been and will always be a completely distinct set, with only coincidental overlap if at all.

It's almost like people think that the phrase "relevant ads" means interesting to the person viewing the ads. Instead, it means you are relevant to the person buying the ad, so Googs shows you their ad. It means you are in the age range and income range, and possibly the geographic area that the person buying the ad placement finds relevant. The person viewing the ad is never relevant to Googs.

Because someone is paying Google to show those to you.

Because they need to hide some of what they know about you. There have been cases where they (in this case target not google) knew a 14 year old was pregnaunt - but the ads for things she needed are sensitive. So the industry has learned everyone gets a few ads that don't apply just to give cover for those that do but someone doesn't admit to.

also some ads really are to everyone. You may not be in a place where you would think about a car, but car makers don't want you to forget you could just in case your situation changes. They also want you to think of some goods as luxuries so you are impressed when you see someone who does have it.

> Because they need to hide some of what they know about you.

My favorite example of this is in the desktop web version of Google Maps. If you search for some place and try to plot directions from “Your Location” it will prompt for the browser's Geolocation API and will refuse to give directions at all if you don't consent to the prompt: https://i.imgur.com/fIQswnD.png

This is despite the fact that it opens the map with a perfectly-centered and reasonably-sized window around my current location. I have never seen this fail when not using any sort of VPN that moves my GeoIP. They could totally give a reasonable mix–max time estimate based on that window just like the one they show for variable traffic.