Bad setup...
If you consider how many aircraft use the SFRAs and VFR corridors, this is a very unusual accident.
May have been a tough setup for see-and-avoid - both a/c flying south towards the sun, silver-gray helo climbing in front of a low wing airplane, ground clutter, probably lots of Saturday chatter on CTAF...
What I find really sad is that a TSO-C166a (ADS-B) authorized transponder might have saved the day - for the PA-32R it probably would have cost ~ $3500. I highly recommend the upgrade even if you don't fly near Class B - I can read the traffic around me well on the screen of my GNS530W and usually see it well before ATC calls it out.