then you presell it. meaning you sell something that does not yet exist. if X number of people buy, you build it. if too little people want it, you return their money and say sorry.
then you deliver the product in as little code as possible. if its just information, write an email instead of building a fully responsive javascript react native reflux multi tenant fully distributed app.
yes, its not called reflux. but thats what it induces in the developer.
edit: thats how you presell products that are sufficiently easy to make. if you are looking at bigger projects like, say, a fusion reactor - you dont presell your customers. you presell investors. you do that by saying "heres the paper weve written as postdocs in university, we think we have a decent shot at making this happen". then you take the money and build the first step of your roadmap. then you go back to raising and presell "see? weve built feature X successfully. now we need more money to build the next thing". and so on, until you have a product.
the process doesnt really change, just who you presell.
