I’m sure it depends, but once a prototype is made and software developed using a premium kit like the Spider, the various components identified, how does one go into making a ‘production ready’ product? Is the process a matter of purchasing and assembling each individual part and assembly them or does the various components get integrated and built into a single functioning board?
You could do it either way. You could purchase and assembly Gadgeteer components, or you could purchase the actual components and integrate them into a custom-made board.
A custom-made board is generally significantly cheaper under one of two conditions: 1) you’re capable of designing it yourself, and you’re planning to assemble it yourself, or 2) you’re planning to manufacture thousands of products.