People pay for products that don't exist all the time. That's what contract software development is all about, for example. Ditto vaporware, Kickstarter, and "coming soon" features of existing products.
And, as mentioned elsewhere, people can think they are about to pay for a nonexistent product. Once you have proven willingness, there are a variety of ways you can finesse the issue of not actually having a product.
And, as mentioned elsewhere, people can think they are about to pay for a nonexistent product. Once you have proven willingness, there are a variety of ways you can finesse the issue of not actually having a product.