Put simply flying a helicopter is a motorized skill, Which most people can learn. All it take's is money, practice, hard work and experiance, The more experiance the better it get's, ie judgement and recogniseing your limit's get's better with expeiance.
You don't have to be superman or superwoman.
For TC you say you've failed lots of students over the years, In eight years of instruction I've only had to tell 3 or 4 people that flying wasn't for them. Maybe that's the differance with the mil & the civil side of thing's or maybe you need to address your method's of instruction.