TVs are massive, so they don't have to be this small and you can already buy TVs with built in cameras, since it can be used for video conferencing. Also, this type of tech can already be used to measure ad awareness in stores [0]. It's also starting to be implemented in cars, to check whether you're paying attention to the road while using 'autonomous' systems.

So... This is not really a type of tech that will enable your fears, it already exists, there just doesn't seem a business model for applying it in TVs yet.

0: https://www.unravelresearch.com/en/blog/eye-tracking-in-adve...