Yes to the former, pretty much for the latter - the "training" I recall was less than a minute long and consisted of repeating one or two example sentences, hardly anything that would be an adoption impediment to devices like an Echo. The resulting voice recognition worked, in my experience, better than that on modern Android phones.
I'm pretty skeptical of this. Apple has a pretty good commitment to privacy, one that is costing them on the AI front, and as far as I can tell they still upload Siri audio to the cloud for processing. If this was easy to do 10 years ago, I think Apple would at least offer as an option.
I have difficulty believing this. We had good speech recognition on <$1000 devices 10 years ago.