On my first aircraft type we had a voice activated auto throttle. I don't think any of the modern Airbuses or Boeings have that.
The only time it did not work was if I was asleep or left the flight deck.
I had those in the 747 Classic. Most of them worked in Standby Mode when I was off the flight deck, especially if the FO was asleep. However, they tended to lapse into sleep mode in cruise...