Modern minivans are crossover SUVs with sliding doors.
Best selling minivan: Chrysler Pacifica... 203 inches long, 80 inches wide, 70 inches tall The larger version of the Jeep Grand Cherokee, already one of the largest crossovers?
204 inches long, 78 inches wide, 71 tall.
The weight in either case is about the same, 4400-4900lbs depending on options.
It's not that minivans have gotten bigger... it's just that they were already HUGE, to the point where even SUVs are smaller.