When I was working as a consultant I literally doubled my rates in the space of two years by simply not caring if I lost any gigs because of it and that was staring with a hourly rate of 3 figures.
At the time I was following the advice I had picked up from other consultants - never leave money on the table. I had enough money in the bank to retire indefinitely, but instead of simply walking away my aim was take as big a cut of the pile as I could get it.
Five years later I was sick as hell of the work, so I did walk away but the opportunities in that niche were rapidly fading by that point. There was probably less than a year's worth of work left anyway.
At the end of the day, whatever works best for someone works best for him. I would just caution against intentionally backing oneself into a corner. Sometimes we do our best with our backs against the wall, but that doesn't mean we should seek to put ourselves in that position.
I have negotiation skills in spades. But I tend to be a doormat. Being under the gun has been extremely uncomfortable but is getting results in ways that simply studying the subject intellectually was not. Getting over some things has been terribly difficult for me.
My situation is complicated and a comment or two on HN won't convey it. If we had more time to talk, we might find we agree more than it seems.
Peace.