I think the problem is that even if suggested idea is good and executable, usually these idea-people know little about nothing how to execute the idea. Typically they know nothing of industry, running a business, web, planning, making products, design and never nothing technical. Programmer should just figure out all the features, design and business plans while programming.

My advise is that you have to sell the idea to programmers same way you would sell the idea for investors. You have to do your homework, have some plans, and make clear what you expect from them and what you can bring to the table(eg. money, connections, expertise). You won't go to investors asking for millions with a idea written on a napkin.