We do not know what the Crew's thoughts were or perhaps can know exactly what kind of profile they had in mind.
The takeoff point was a ridge line, dusty, LZ with sloping ground before them but with some trees as barriers. We might be able to figure out how high the trees were and that kind of thing by going back to the NTSB Report where they plotted the impact height on the tree and all that data.
You are exactly correct when you state....if you run out of power...and the Nr Droops ....and you have not rotated forward....rejecting the take off is easy....that being a vertical descent back to your takeoff position that is still right under you.
We also know that a Takeoff from the ground provides better performance as compared to a take off started from a Hover.
The CVR recordings seem to indicate that is the profile used....that being a Take off from the Ground with no Hover Power Check done beyond considering weight and balance data, OAT, and recollection of the previous two takeoffs from the first two sorties from that site.
If that is the case...no actual hovering of the aircraft to confirm what power the aircraft was demanding and what reserve was available...then in my view the Crew made a fatal mistake that day.
To be fair....one would really need to be in the cockpit...and seeing what lay before the crew to fully grasp the situation. Just how high were the barriers, how steep was the decline in terrain, did they think they would be able to trade height for airspeed as is done from a ridge line if there is sufficient terrain clearance, and all those considerations.
It is a dead certain fact....If you do not do a Hover Power Check which allows you to confirm handling and power....you have no chance to actually confirm the performance of the aircraft. Old Pilots get that way by being careful in how they go about their business and a hover check is the very insurance one can have. Guessing wrong can prove to be a serious problem.
As they drooped Nr on the earlier takeoffs, that should have been a clue.
I firmly beleive that over time they had become used to seeing some droop on takeoffs especially if the company had the culture it did about using over spec engines as an excuse to carry more weight. Add in the crew being unaware of the bogus Weight data provided by the company and compounded by the false performance data as well. I see them falling into a trap.
They should have been doing a Hover Power check for each takeoff as a good safety habit.
Let's open up another bucket of worms about the FAA and USFS mindsets.
Should the Industry and the USFS and FAA start using Restricted Weights in consideration of OEI operations should an engine fail?
What kind of performance would this passenger carrying aircraft have had if it had experienced an engine failure during the take off, cruise, and landing? Is the FAA supposed to require Large Helicopters to operate in compliance with Part 29 performance standards?
Right now....if those large aircraft hauling passengers are not doing so....are they in violation of Part 29?
Does Safety for the Passengers not mandate they do?