The motor is designed to use additional power generated when the ICE is running. The battery is smaller than the Ford Energi or the Volt and just has inherent power output limitations. The upside for the smaller battery is lower cost and better (luggage) storage capacity. Life is full of trade-offs. Would you be happy with the EV City mode that the European PiP has? It's as close to what you want as I can imagine given the limits on battery power output. I suppose it's possible that the U.S. model PiP is capable of supporting EV City but just doesn't have a switch wired up to it. Toyota has done things like that in the past. For example, the gen 1 U.S. Prius didn't have cruise control even though the Japanese model did. People figured out that they could order the Japanese Prius cruise control steering wheel stalk and just wire it up to the U.S. Prius and it would work (eventually, Toyota came up with an official after-market install kit).
I might try this experiement (carry 1 gal gas in can)...but it will take me a couple of months to get near empty on this tank of gas so don't wait for me. Mike
My 2002 Gen I came with factory cruise control. I recall that the 2001 (first model year for the Prius in the US) did not.
you may want to carry 2-3 gallons as some have reported needing this much on older models to get the system reset.