KPHL
Please enlighten me as to how building flight time in a Cessna 172 is going to make me a better Captain or First Officer in a Boeing 777...
If anything being a SO will make you a better Captain or First Officer... you have had several years of following your colleagues in the flight deck and learning from them...
To be honest this just shows how little you understand about aviation and what being a pilot for CX involves.
I am not saying guys who joined through the cadet scheme are bad pilots, far from it.
As an SO you sit there in the middle of the night watching a tv screen as waypoints go by on the green line. You mark down the time on a sheet of paper and once every hour do a fuel check. You watch the CN and FO type stuff into the FMS and chat about the approach, then the autopilot flies the plane to about 500 feet at which point they normally do a manual landing. Almost all pilots at CX have never had any serious problems with the aircraft and chances are you will never see anything out of the ordinary. In 3 years we have never even had to really consider diverting.
In GA you WILL have problems if you get 3000hrs doing it, the prior minimum requirements for DESO (some got in with lower but not many). You will probably have diversions, engine failures, unusual situations that you could not even have thought of. Most of this will happen with you in charge, you will have to make the decisions, you will have to evaluate your actions. This is why you are better prepared to be a CN with an airline as with an airline things usually run as planned and you may get into that left seat of an A340 having never had to make a difficult decision in you 12 year of flying.