Maybe I have something to add..
I've never really wanted to strive at work.. I've always had an attitude of do well the things I'm asked to do, but don't go for promotions or try to find extra things to do, but given that I've probably risen through the various ranks at about the same rate as everyone else.
Now though.. I'm really bored by work, its certainly not bad or unpleasant, its just ho hum, so now I'm counting down the 5 years until I'm FIREd (I'm now 46).
So I sometimes think, was there an alternate path, if I'd really pushed myself to do interesting things at work, would I have had a much more satisfying career, I really don't know, but in retrospect, I think that one of the probable costs of not being motivated at work, is that you end up in a boring position.