"I'll ask again...exactly what is it that you want the younger readers here to take away from these posts?"
That there is a significant chance that, no matter what you do, you might not make it to the top of the career. It's like a pyramid, the closer to the top you shoot for, the less likely you'll make it. If you'd be happy in the middle, then the more likely you'll make it. Not everyone who simply "wants it", is gonna get there. There is a certain amount of luck and timing involved that you can't control.