Earlier quoted context omitted.
The reason the "phones are listening to you and targeting ads based on what you say" thing is a classic conspiracy theory is that it would take a genuine secret conspiracy to pull it off. Think about how many people would need to be in in the secret and actively lying about it: employees of phone hardware companies, and ad tech engineers, and execs at these companies, and their legal teams, and every contractor they…
I don't think any such conspiracy or secret-keeping is required; one need not attribute any of this to malice which can be attributed to incompetence. There already exists a system, on everyone's phones, which is listening to audio at all times, occasionally activates in response to a wake word and runs search queries and such from it. The point of this system, when used properly, is intended to take a recording of y…
Nobody ever describes that behaviour, though. They don't say "a) we had a conversation, b) our smart speaker suddenly interrupted and gave us some search results, c) I started seeing ads based on the conversation" - b) is never mentioned.