I think this may be because of the sticker shock...I mean, personally, I've tried other programs as well, and while they aren't cheap, they also don't require you to plop down $10-20,000 all at one time up front (in many cases).
It's more managable to drop a hundred bucks here and there over the period of months/years and not really mentally absorb the overall cost of what we are trying to do as opposed to having to shell out thousands of dollars all at once. I think that really hits home for those of us who are self-pay. I know it was for me...having to pay out of my own pocket is a constant reminder of what I have commited myself to and really drives me to succeed.
For me, it's about taking responsibility for the money I spent and trying to make sure I get every dime's worth out of the procedure.
Of course for all of us there is an emotional and physcial investment we make, and that in and of itself is generally enough to motivate us to succeeed.
Anyway, just a few thoughts as to why the cost of previous programs may have been easier to accept as opposed to the cost associated with the lap band surgery.