Fair to come to that conclusion considering there's nothing on the pixel 6 specs page about it. But it's also worth considering they may have included the 21 volts to charge laptops/pixel books, without someone measuring with a voltage meter, we don't really know if the PPS goes beyond 11 volts (which is what most PD3/PPS chargers seem to max out at.)
Semi-related/unrelated, but I have been using the Belkin 25 watt which lists the following specs:
View attachment 5448643
and has maxed out at ~4.2 amps (at 3.8/4.2 depending on charge) which is around 15-18 watts.
I received the google charger today so we'll see if it charges any faster.
Maybe someday manufacturers will list charging specs considering the current cluster$#@! of different proprietary charging methods that have become "standard", and if they really expect people to reuse their older chargers for a new device.