Just last week I bought return tickets from Rome to Milan for the days around Christmas on Italo (the only competitor for high speed trains) and I paid under 50

Just last week I bought return tickets from Rome to Milan for the days around Christmas on Italo (the only competitor for high speed trains) and I paid under 50 euros return. Also the distance is not 420 km, but closer to 600 (it's 480 km as the bird flies). And regarding stops, you can get one that doesn't stop at all and it's 2h40 IIRC.