Frame interpolation converts 24p to 60p? If they would convert to 72p, would we still see the soap opera effect?
With my CRT I'd use 1080i72. But there wasn't any FI going on, I'd just show the same frame three times. That would get rid of the strobing effect with 3:2 at 1080p60, but wouldn't make the motion any smoother.
Anyway, 1080i72 never did bother me, and actually looked better than 1080p24/48, etc using LCOS or LCD, which just looked jarring.