You must not be referring to Harley riders!
It depends on the rider. I took my driving test on a big twin decades ago and passed the first time, and beat quite a few high performance cages light-to-light in the day.
Horsepower to weight ratio is still superior (even with CAFE standards), and I can go places the cars just won't fit through.
I'd say in competent hands, the Harley still can out-accelerate and outmaneuver the average cage--hands down.