That's an excellent point that I haven't seen anyone else make yet about Kickstarter, and does help to explain a bit of their runaway success. Though it does seem rather obvious that a higher level of transparency and a stronger customer-maker bond would also be useful in capturing a greater amount of the consumer surplus than an average, faceless megacorp would.
You pay however much you are ready to pay.
Traditionally if you price a ware 100$, you'll lose all the money from those who can only afford 10$, and if you price it 10$, you lose all the extra money from those who would have paid 100$.
With Kickstarter, some people pay 10$, some 100$ and some 1000$, and they are all very happy about that.
This is achieved by: Giving nice perks for extra money; Buyers understanding that by paying less they only steal from themself.
That's not that uncommon a pricing model in the arts even pre-Kickstarter. You've got the $10 CD, the $25 limited-edition CD with bonus tracks, the $100 super-limited leatherbound box set signed by the artist, etc.
But don't the different "tiers" generally offer different products (or multiple products, special goodies, etc)? If you just want the basic watch, you aren't free to "pay whatever you want to pay" -- you have to pay the asking price, just like everyone else.