Why does technology implementation need a people or customer-focused approach?

Technology is more of a service provision industry. When a developer is working on a new software/ application, their focus is on the end user who is the client. The best approach to implementing or introducing a new technology is first by having a concept/prototype which u will introduce to the world thus to see how the people respond to it and then u can have a clear picture if it's viable to continue with the project or not. Hence, the end users opinion are very important to the developer because he/she is sort of working for them. They are your employers and hence a developer should work with them if not for them..