Comment by ValdikSS

In the world of auto-updates of software and firmware, even the hardware which is now completely legal and crap-free, could convert itself to a proxy or ad network later any time.

And don't forget about counterfeit products (which look like original but different in firmware) and supply chain attack vectors, which are really, really common.

If you want to buy something as simple as a feature phone, going to a store with 10 of them will give you at least 1/10 chance to buy a phone with a trojan/backdoor.