I agree, experience is key. I worked my way through flying air cargo on a Cessna 206 and Chieftain until I got a lucky break with a Citation. What I learned and the problems I faced while trudging through weather in mountainous terrain sculpted the thought processes I used on jets. An initial training course and all the sim sessions in the world can't teach you what to do when your deadlines are running tight, weather is down, and you find a problem with the plane that may or may not be deferred.
I spent some time working for a company that contracted maintenance to airlines and when dealing with the "cracker jack pilots" at the regionals the experienced mechanics would groan. The pilots often lacked the ability to be independent decisions as a crew and would defer PIC decisions to pilot management, union personnel, and maintenance control. In the corporate world those pilots would be eaten alive.
There is something to be said for having to make your own life and death decisions without being able to defer those decisions to a higher up. It hardens your resolve and sharpens your judgment. You can't ever teach those sort of things, but that's what I look for in a pilot. When look to hire a pilot to act as PIC (or SIC even since I eventually want SIC's to be PIC's) I would take someone with 2500 hours hard King Air time versus a 737 rated 800 hour pilot and I have done so many times in the past.
Stick flying accounts for only 10% of what it takes to fly a jet, 90% is judgment and general experiences.