And some have a manually-operated lever, which is completely silent.

The ones out there now are wonderful, but quite huge and expensive because they rely on AC motors which sadly aren't very power dense and don't scale down well

Rotary pumps aren't that big -- most of the premium espresso machines with vibration pumps are actually bigger than the ones with rotary pumps, i.e. compare a dual boiler or heat exchange vibration pump like Synchronika with a Linea Micra or Lelit, with two boilers and rotary pump.