If you are a target of the NSA or some other state actor, then perhaps. If not, and you take a bit of care to disable the voice assistant on your devices (Siri, Google. etc), then you should be fine.
at the end of the week, we both saw no increase or even a mention in our targeted adverts regarding snowmobiles. likely what is happening is that you searched something somewhere on your phone, then brought it up in conversation, then saw an increase in ads related to that subject.
Also a fair number of people live where a snowmobile isn't practical but have a cabin where they are and so they will be making weekend trips to where they are practical.
Your point stands though, anyone who lives in the wrong area is unlikely to be targeted if the only indication they might want a snowmobile is home conversion. If you are serious you will do other searches (tracked for sure), and have location history in a target area (might not be track able, these area often have poor cell coverage)
While I do respect you and your spouse for trying this experiment, it's entirely too small a sample size to really prove that this doesn't happen. There are a ton of variables involved, the biggest being which advertisers may or may not be listening in at any given time. It's hardly a controlled experiment, and I can't say I can put any stock in it.
It also does not prove that it is observer bias. I have had things pop up that I am %100 absolutely positive I never in any way shape or form looked into, yet there the ads were after a short conversations with others who did have an interest.
It makes sense for them to target by IP, so if one person in an office is researching the product they can start targeting the entire office and maybe get their ad in front of an exec who can make a purchasing decision.
Your message is basically "You're already screwed, why bother trying?"
Why act that way? Who are you helping?
If you support privacy, then people taking steps to try to share less data ought to be encouraged, right?
Maybe it's not perfect - But it's worth trying to do better.
I take active steps to minimize when and how the microphones around me listen in. In no way do I subscribe to the idea that "we are already screwed".
Please do not take the worst possible interpretation of what people say on HN. It's in the guidelines and generally looked down upon. This is not reddit.
Let's say person A was doing research on a product they're interested in buying. That product category is now associated with person A. Person A goes and visits person B. Because our phones track where we go by default for most people, now there's an association between Person A and Person B, and a potential likelihood that person B is also interested in that product. Thus the occasional ad shows up for the product Person A was researching. Since Person A and Person B are friends, it's possible Person A will talk about the product they're interested in. Person B now notices that they're getting ads for the product that Person A talked about.