I think that most people's interest (including mine) in doing YCombinator or TechStars is not really the funding. It seems that you'd be much better off in this case just saving the 6 or 8k yourself. Rather, the network and guidance in getting your idea off the ground seems to be the real value.

Exactly. The value of each of these programs is directly related to the guidance, advice, and networking involved. Having a good selection process is also a good validation of teams/ideas.