Nobody considers the phone network to be equivalent :)
Even current smartphones do not turn on their microphones outside of a call, unless one has made the huge mistake to turn their assistants on, or there's an app recording - and at least on iOS that's controllable by permissions and marked clearly when the app is in the background.
Modern smartphones have assistants that "listen all the time" in the same way that you're saying that smart speakers do (namely, they look for a wakeword).
No, modern smartphones allow you to have assistants that listen all the time. Disabling those is one of the first things I do, and I'd be pretty unhappy if it turns out those are still listening and wasting battery (even aside of privacy issues).
No the parent is right. They are not "listening all the time". They're essentially sleeping while a separate process handles the audio stream looking for the wakeword. When it finds the wakeword, it then "wakes up" the assistant which reprocesses the audio snippet to confirm the wakeword is really there (using more expensive analysis), before then actively listening to the rest of the audio.
Back in the 1990s, their hardware design was simple enough that any mass surveillance would inevitably get exposed when the odd hacker took his device apart.
These days, I'm not sure at all. All we have is the law as a deterrent, and that's weak, especially to governments.
Even current smartphones do not turn on their microphones outside of a call, unless one has made the huge mistake to turn their assistants on, or there's an app recording - and at least on iOS that's controllable by permissions and marked clearly when the app is in the background.
Anyway, smartphones are creepy too.