It takes little imagination to see that any design, engineering, or mechanical failure in that environment is followed by virtually instant and catastrophic loss of the aircraft.
My point was not that helicopters will become as simple (and reliable) over time as airplanes, but rather that cumulative experience is a significant factor in identifying how to improve designs, and that when there is as much cumulative experience with helicopters as with airplanes (40 more years plus or minus) , we should expect to see great improvements in safety and reliabilitry vs where we are today.