I think Kickstarter could add a maximum cap in addition to the minimum funding requirements as some function of the minimum. This would minimize Kickstarter's risk of over-subscribed products (but would obviously make them less money in many cases) and push further sales into the regular retail world. This would keep Kickstarter closer to what I believe its true intention is - get products and art off the ground, not sell your first $10 million.
I the long term I also think this is better for the campaigns - a lot of hardware projects seem to struggle shipping if they get a significantly higher number of orders than predicted. I'm sure in the moment it's exciting to see how many orders you can pull in, but painful in the long run when it is difficult to deliver on your promise, especially if you're planning on building a long-term sustainable business.
That's actually a really important change that they need to make. If you are trying to raise $5,000 to make 200 widgets by hand, and suddenly your project takes off and you get $500,000 in pledges, then as much as everyone would like to say "that's a great problem to have!", well, it's not.
This point is counterintuitive but here it is: Assuming that there are relatively rigid time constraints, you might be able to make a profit at 200 units, and a profit at 200,000 units, but not at 20,000 units. This is because there are thresholds where you suddenly have to invest in infrastructure, and setting up infrastructure fast is particularly expensive.
If you're raising capital to produce your widgets, you can lay out a business plan and predict with reasonable certainty that you need to sell X widgets before you can break even. You present that to investors and they decide if they think you can sell X widgets.
On Kickstarter, you are implying a fantasy claim of arbitrary linear production scaling that says "I need $25/widget and I will make however many everyone wants!" And hell, that doesn't even work for selling commodities.
So what the model should be for people starting a business selling a tech product is that they say "We're developing a prototype, and if you pledge $X you can get a prototype". Then limit that to a small production run and raise enough money so everyone can involved can quit their job. Now they have time to look for investors, and a great proof of concept that the idea is marketable.
Well, that's actually possible. You can limit the number of backers for any pledge level. So you can have a maximum of 50 supporters backing you to receive a "foo" and another number of "bars" for a different price.
So the usual place where you see an unlimited number of backers is for digital products. See the Amanda Palmer or the Planetary Annihilation: They had limits on any backing that required a physical or personalized goods, but unlimited pledges for digital-only pledges - and there the assumption of "the more I sell, the more I gain" holds true.
The other side to this is that higher numbers give them the benefits of scale. Ordering 1000 rather than 100 of a particular part allows you much cheaper prices. Which means higher chance of success. Having to deal with a few million dollars worth of orders is a good problem to have. Much better than the same product, but only a few thousand.
I the long term I also think this is better for the campaigns - a lot of hardware projects seem to struggle shipping if they get a significantly higher number of orders than predicted. I'm sure in the moment it's exciting to see how many orders you can pull in, but painful in the long run when it is difficult to deliver on your promise, especially if you're planning on building a long-term sustainable business.