I could go on for pages about a psychological thing called "Imprinting", but the Reader's Digest version is this; when you begin your career, what ever field you choose, your first couple years 'imprint' your mindset for the rest of your career, and you will subconsciously revert to that whenever there is a fork in the road, you'll choose what you were imprinted with.

If a guy goes straight into the office (be it ALPA or a CPO pencil sharpener) that's where he will feel most comfortable later in life, and when ever a choice comes up, he'll chose office work over the cockpit.

I saw it in the Military, and I've been watching it at Delta for 30 years. Some guys just love putting on a suit, going to an office with their name on the door, and the biggest decision they have to make all day is where they are going for lunch.

Most of us chose flying so we WOULDN'T have to sit in an office all day, but some guys are more comfortable there, and they get to sleep in their own bed every night, with weekends and holidays off too, while being paid 'what they can hold' but never have to go sit reserve on it. The skies are probably safer with those guys sitting at a desk anyway.