The part you?re not getting is that the airlines is a handful of large companies that control many flights/airplanes and crews, there mission is to complete all those flights safely and they have the control over their many crews and there equipment, so the management of one company can impact the safety of thousands of flights a year, for the better or the worse, these days they are doing a good job, they also have huge interference/interaction with the FAA/NTSB etc. to help facilitate there good record, this is all because they are responsible for thousands of lives each day, lives who paid and have a very reasonable expectation to get there in one piece.
General Aviation has thousands of individual owner operators each one responsible for his piloting and training and his airplane, each single individual responsible for his single flight that day, which by the way he only decided to take 5 minutes earlier with no particular path or goal in mind other then to go for a flight to see the country side or do some acro or grab a hamburger. You get the idea,,,, we are not the airlines,,,, what has worked for them would be very expensive and intrusive and the end of Private GA.