I don't have any specific evidence on hand, but I do know a lot about the technology and companies involved from working in adjacent fields (cloud architecture) and it is absolutely plausible that they can and do. If they are not doing it already (and I believe it is highly doubtful that at least some devices do not already do this) then it is certainly on their roadmap. Many consumer IoT/media devices have invisible, hidden wireless networks built in and have for years. If it's advertised, it may boast some sort of "quick connect", "auto configuration" or other convenience feature, it may be genuinely required for low-latency/quality-of-service (for example on most modern TV services which supply the channels by IPTV behind the scenes), but it's always on, it's always listening, and it's only a friendly partnership agreement away from being used for whatever "legitimate" purposes a company may dream of.

Tech surveillance is extremely out of hand and has gone so far beyond anything would consider reasonable, I understand that you would instinctively reject it as too extreme to be believable. But in the industry it's completely normalized and they don't even give it a second thought, it's just business as usual.