Amazon pioneered double-dipping by offering discounted Kindles as long as buyers consented to ads on their lock screens. This model of underselling their own products in return for deeper market penetration coupled with selling their own ads to up-sell their own additional products and services has now become de-facto. This is why Fire OS, Chromecast/Android, and Roku devices are so popular: they offer cheap and minimal hardware in exchange for your personal information.
As has been stated, if the product is too-cheap/free, you personally are the cost being exacted, you and your personal/private data. If you don't care, carry on; if your ownership of your own data matters, demonstrate by voting with your wallet and using privacy-focused services.
The same applies to smart TVs and some other "smart" devices.
When I replaced our failing DVD player with a BD player that had streaming capability a few years back I first went with Samsung. I'd read complaints about their ToS and privacy policies, so I read everything to which I had to agree carefully. It all seemed ok, until I went to try a streaming service and was presented with a whole new raft of stuff to which I had to agree to activate it. And there it was: Text to the effect of, in activating that stuff, I agreed to let them track everything I did with the player, including what DVDs/BDs I played, to be sent back to them and shared by them however they wanted.
I took it back and got a DVD/BD player that didn't have that nonsense.
The ToS for our new LG TV, when I went to enable its "smart" features, contained the same kind of verbiage. I did not enable the "smart" features and it remains disconnected from the network. I re-connect it occasionally to check for firmware updates.
I imagine few people bother reading the stuff to which they agree when they buy, enable, and use this stuff.
Yup.
Once read an article, a couple years back, explaining why, of two TVs that were essentially identical in all respects, save one was "smart" and the other not, the "smart" TV was far less expensive. That's why.
Yup. That's why the only network-connected "smart" devices we have are all Apple. Apple has very clear privacy policies. They sell you products. The don't sell you, as a product, to others.
There are lawsuits all over the place now accusing Google, Apple and Amazon of selling data that was supposedly turned off or that the end user was never informed about. In my estimation the one with the best chance of winning is the one that argues that the Terms of Service are so ambiguous and complicated on purpose to keep the average user from even trying to read the them. I've got a bunch of degrees and some of the TOS are so bad that that it would literally take a lawyer to comply, much less understand them. Years ago Microsoft got into trouble for actually writing TOS so that parts contradicted other parts on purpose.
We live in an information age but that doesn't mean that big tech is allowed MY information, to do with as they wish.