The types of developers you want creating your prototypes are those that can justify charging $200+ per hour because they have past business/user experience to truly understand what you want to achieve from your project as opposed to what you've specified.
The number 50 was for illustrative purposes. Not sure why that's so funny. Ok 100/hour and 35 hours look at that. If you can get the projects done in a tenth the time suddenly you're getting a lot more than that figure.
Also as another has pointed out, justifying 200/hour and beating the competition is very difficult in a world wide market. Those in sv may be able to push that high but I can assure you there is many many developers with the same skill set living in much cheaper economic climates where 50/hour is considered much higher than 200/hour is in sv.
The types of developers you want creating your prototypes are those that can justify charging $200+ per hour because they have past business/user experience to truly understand what you want to achieve from your project as opposed to what you've specified.